I have a memory stick with 200 000 write cycles and wanted to know if it would be okay to keep saving files every five minutes from Microsoft Word. Will this wear it out - should I save less frequently, e.g. every week?
200,000 write cycles is a lot. You should have no problems with the memory stick at all. Just write to it normally. If you were to push 100 write cycles every single day, 7 days a week for 12 months, that memory stick will probably last you 5 + years. If you write less than 100 times, then it should last longer if the IC doesn't prematurely give out. That's if the 200,000 write cycles is accurate.
I seriousy doubt you'll write 100 times a day though, lol. You are just fine. By that time, new memory sticks will be even faster and better anyways.