Would you wear thrifted clothes to work

I work in an office environment, managerial job. But after pregnancy my size has changed so much 12 to 16 then back at 14 I cannot justify spending a lot of clothes till I go back to a permanent size. I'm not sure how to thrift for office wear? What brands to look out for ? I don't want clothes that have shrunk or faded.Do good quality officewear even exist in opshops? Late thirties thanks.