Just try not to cross your chain too much.
I have 3 chainrings on my bike. I have NEVER used the little one except playing around when I first got the bike.
I use the middle one most of the time, because with the gravel roads and hills that I ride most of the way, it keeps me in the middle range on the back for the most part. When I get into the flat, paved areas, I usually shift up to the big chainring, because in those areas I want a gear up above what I can get with the middle ring.

Bottom line; shift mostly with the back, but avoid running big chainring with lowest rear gear, or little chainring with highest gear. That won't really hurt much, it does wear the chain a little more, but I don't think it's that big a deal. It's not like doing that up one hill on your ride every morning is going to cause you to have to replace the chain in 1K miles instead of 2K miles. If it makes a lot of noise and that bugs you, then do what you like.