When can I remove permanent redirects?

Hi, we rebuilt our site last year, and have also been doing a lot of SEO work. As a result, I have over 2000 redirects in my htaccess file. I think by now I can start getting rid of a lot of them, as the crawlers should now have stopped indexing these pages.

But how can I know? Is there a tutorial that takes me through the steps for doing this? Example: in October last year, our page about.html became our-story.html, and I added a redirect.

Can I now take that redirect off the htaccess?  site is www dot magic kitchen dot com.

Other examples:

1. We renamed products, so what was dutch-apple-pie.html  is now dutch-apple-pie_7321.html. That was also back in last October. There are hundreds of these.
2. Old products that are now off the site: RedirectPermanent  /menu/Vegetarian/vegetable-lasagna.html   now gets redirected to /menu/Vegetarian.html

Thanks for any and all advice!