I'm more relaxed about word substitution. I used to get annoyed at myself for avoiding words and using other words that were less than ideal. So I started forcing through the word I wanted to use, but sometimes I would realise later that there was a better word I could have used. So now I take time to consider my words. Sometimes I need to prepare to say a difficult word, sometimes the easier word is better. And sometimes it really doesn't matter - there are many ways to say things, and it can be fun to find creative ways to express yourself. People who don't stutter also change words, especially those they find hard to say. And that's ok.