Field length - how much does it matter?

Basic but very important question - how much should I be concerned with optimizing field size - for example, we have a table of vendors, maybe 1000 records, will grow to 2 or 3 times this size, but we have kept all the text fields at 255 characters - most of them are address, phone, other fields that probably can do with anywhere from 10 to 50 or slightly more characters.

If is worth going in and shortening field lengths?

Many thanks,

Robert