What cog are you on when you change from big to small ring?
Are you cross-chaining? If you're using the the small ring, the best
way to keep things running best is to stay in the bigger half of the
cassette, maybe one or two cogs into the smaller half of the cassette.
Likewise if you're in the big ring, try to stay in the smaller half of the
cassette although you have more leeway to venture into the bigger
half (because chain can't rub on the big ring because of chain angle).
Straying too far into the bigger half of the cassette puts a lot of side
load on the chainring and chain (e.g. big ring breaking while in 53/23 combo).