Other than Waxing strings often...even if not using wax good before storing...
Storing conditions are
very important...store in cool DRY, room temp..best laying flat in protective bow case...however beware some foam in cases can attract moisture...avoid high heat or cold or combinations..
I know of several bows exploding in bow cases when strings let go...
Modern bows need little else for maintance as bow, all bearings are sealed and self lubing..one can put a coat of Olive oil [oderless] or gun oil [which may be smelly] on all exposed bolts,screws, nuts etc...
The main limb bolts are the only thing that need a periotic lube/clean with white/lithium type grease, and that should be done at a PRO shop when strings are changed...or if you have a press and feel confident on complete tear down...
At three years your strings will be stretched or have "creeped and settled in" as string manufacturer like to say...
Which means the bow is most likely way out of tune, which effect bow draw lentgh, bow weight, timing, idler/cam lean, brace height, axle to axle length etc which can/will in turn effect accuracy and performance...
Strings if waxed will most likely be in good condition, but take it to a PRO shop and have the bow tuned would be a suggestion
Neil