if you have a tailor or dry cleaner that you trust, ask them.
I think it depends on the article of clothing. Some of my pants were okay belted for much longer than others were.
I know what you mean - business clothes are pricey. If you still have a ways to go, I would only buy from thrift stores. Or only buy a couple of pairs of new pants. If you have a 'ritzy' part of town close by, check the thrift stores in that area. You'll find some GREAT buys.