Microsoft Licencing

For the purpose of law and MS statement that should not be done. But it works at least I had no problems with using same procedures.
I run office uninstaller which remove everything inside package(word,excel etc.) then everything went fine when installing. In previous cases when office was not removed before it could happen we had to activate office via phone. But we mainly use this when we upgrade PCs with new disks.

You can find tool here: https://go.microsoft.com/?linkid=9815935 

I used this on all versions from 2007 to 2016.

Had problems if I wanted to start it on vista or older.

Your End User License Agreement (EULA) tells you whether you are permitted to move the software from one machine to another. In Excel 2010, you may find this agreement using the File...Help menu item, and then clicking the hyperlink for Microsoft Software License Terms. Retail versions generally permit you move the software to a new machine, but the less expensive OEM versions do not.

You should also be aware that older versions of Office have a limited life. Mainstream support lasts five years from initial release, while extended support lasts up to 10 years. After extended support ends, there are no more bug patches--even for critical vulnerabilities to malware. You probably don't want to take that risk in a business setting. Office 2010 ends extended life on October 13, 2020. Office 2013 (with service pack 1) ends extended life on April 11, 2023. https://support.microsoft.com/en-us/lifecycle?p1=16674 If you install either of these versions on your new computer, they will be out of extended support before the end of the computer's 6-year life.

I personally suggest getting on the Office 2016 subscription bandwagon. The price is reasonable, the features are great, and the software is less prone to crash/hang/freeze than any previous version.

Going Office 365 is a potential waste of money.  Or could offer great value.  It really depends.  Do the math.  At $144/user/year, that's $864 over the 6 year life a computer (assuming you keep going with 6 year lives).  Buying an office license can cost you between $400 and $550 with NO EXPIRATION.  Now do the math... 41x$864 = $35,424 over 6 years of Office 365 ProPlus vs. $22,550 for Office Pro purchased.

You DO need to factor in the added value that office 365 can provide, including always being up-to-date, the OneDrive space, the additional services you may get... but if your company doesn't use those features and doesn't have a need to be always up-to-date, getting on the bandwagon will cost you!

Now, that said, as has been suggested, your license agreement dictates what you can do with the software COMBINED with your local laws.  We haven't read your license agreement - the one YOU have - nor do we know exactly where you are and what laws apply... there's a slim chance you're in the neighborhood of someone who will see this question and can (but probably shouldn't) offer legal advice, but odds are, YOU are the best person to answer what you can do with your licenses by reading them.  And if you think you're area invalidates some of the license provisions, then speak to an attorney (or get a referral from an attorney).  At a minimum, contact the license granting authority to check with them.

And just to be clear -
Licensing Disclaimer
License information provided here is "best efforts".  The comments of the respondents are based on interpretation of the license agreements and their knowledge of the particular laws and regulations in their geographic location.  Laws in your location may invalidate certain aspects of the license and/or licenses can change.  (For example, at least one major nation's laws allow OEM licenses to be transferred to new hardware). "They told me on Experts-Exchange" will not be a valid excuse in an audit.  You need to contact the license granting authority to confirm any advice offered here.

Actually, the lifespan of office is now 7 years.  However, depending when you purchase, it could be less.  That said and as much as I DO NOT advocate using unsupported software, the product likely won't magically stop working at the end of support.  It still does not make the point about what to purchase invalid.  The bottom line is do the match.  Even replacing the software after 5 years still shows a potential savings of $7000 for 41 users.

And a further consideration - it's not always easy to downgrade Office from subscription models and if you have older software that isn't compatible with the newer software, your subscription could force you to upgrade other software or even be unable to use it.  I don't have any specific examples to cite, but it is a possibility.

The math is not as one-sided as Lee W, MVP is making out.

You can buy a copy of Office Professional 2019 Business for $399.99 on Amazon This gives you a license to install Office on one PC, and includes Word, Excel, PowerPoint, Outlook, Publisher and Access.

You can buy a subscription to Office 365 Business for $100/year. This gives you a license to install Office on up to five computers, five tablets and five phones (15 total devices), and includes Word, Excel, PowerPoint, Outlook, Publisher and Access. It also gives you 1 TB of OneDrive storage and free use of the Office Online apps. Microsoft is putting a lot of investment in those Office Online apps, and I promise you that being able to use them will become important during the six year life of your new computers. The extra devices will be handy if a user has virtual machines, both a laptop and desktop, or other combinations of computer/tablet/phone.

The $144 price for Office 365 that Lee W, MVP mentioned is actually $150/yr (it's $12.50/month). It includes everything that the $100/yr subscription does, plus it adds Exchange email service, Teams and SharePoint.

Before Lee W, MVP points out that $100 times 6 exceeds $400, let's look at the rate of return on that investment. Subscriptions are expensed in the current year, while software purchases have to be depreciated--so there are tax savings in favor of subscriptions. Assuming a 25% state and federal tax rate and a five year straight line depreciation for the software purchase, the net cost of the perpetual license is $300 versus $450 for six years of subscription. The IRR function in Excel can compare the cash flows, and tells me that buying a perpetual license gives you 15.5%/yr return (after tax) compared to a $100/yr subscription. The higher the tax rate, the lower the return on the perpetual license. Every place I have ever worked would take the subscription in a heartbeat at that low an internal rate of return.

Microsoft wants to get all users on the subscription bandwagon. The income stream is more steady and they also need to test fewer combinations of Office and Windows versions whenever they make a change to either. That's why they shortened the extended service life of Office.

byundt,

Thanks for putting words in my mouth... I almost choked.  please try to avoid that in the future.  Thanks!

One of the reasons I've been saying DO THE MATH is because there are MANY options both for Office 365 and for Office 2019 perpetual license.  Why are you so averse to doing the math?  Seriously?  Why?

Do it.  I don't know the asker's environment.  He hasn't hired me as a consultant.  But the bottom line is to look at what is needed and what is offered, if you prefer a monthly expense with NOTHING STOPPING MICROSOFT FROM RAISING THE PRICE or a one time purchase that can last 5-7 years.  If the needs are there, go office 365, absolutely.  But if the needs are not don't pressure the guy to do what Microsoft wants.  Subscriptions are great for the business... but not always so for the consumer!

I'll also point out there's a reason I chose the pricing I chose - and it may not apply to the asker - but it keeps things "apples to apples" instead of apples to kumquats.

Office 365 ProPlus at $12/user/year and Office Standard 2019 or Office Pro 2019 are all in essence volume licenses that grant use on an RDS server.  If Access is needed, Pro is needed.  If Access is not, Standard is more than likely fine.  Making the savings even greater!

But, as I was saying to a client today, one of the big differences is up front costs.  I have one client that would prefer to have a 1 time fee and be done with it for years... but because it would be very expensive to cough up the money for 35 people x $400, they opted for Office 365 ProPlus instead.  And I have another client looking at the same situations only they are 8 users, not 35.  

Let me put this another way - please allow the asker to do what's best for his business and not what's best for Microsoft's business!  (And the only way they can really do that is - you guessed it - by doing the math).

After investigating the comment about acquiring Office 365 for $100 per year to allow 5 licences, 5 phones and 5 mobile devices, this is only for the same user and not for 5 users.  In an office setting, each workstation has it's own user and obtaining the $100 per year option is really no option at all.