Plum curculio ...if you want fruit, you need to limit its damage. That means you need a spray after fruit set (petal fall).

Japanese Beetles (possibly Rose Chafers depending on your area). They can be very damaging depending on if they are in your area (they are new here).

Squirrels and birds. Out of all my pests, at the end of the day I think its the squirrels that do the most damage. If you can limit (or better yet eliminate them) you will be better off. Birds are tough...something like cherries have got to be netted and even then they'll get some of them (i've had robins inside my sweet cherries stuck several times). When apples start turning, they'll start pecking them (water?).

You might just want to spray every 2 weeks? (i go longer between sprays depending on rainfall)...

Pears see the least damage in my yard...bugs generally leave them alone. Squirrels get them.

Fun stuff. You'll lean every year a little more about your situation, because every growing area is going to be a little different and every season is going to have some differences (bug emerge different times depending on GDD)...some years are really bad, other years might have light pressure.