Drop link length doesn't make any difference to the handling, you only need to alter them if the the arb or drop links are fouling the chassis, dampers, calipers etc
The other reason is if the drop links are very far from vertical and putting excessive strain on the drop link ball joints, you'll just wear them out quickly but luckily they are cheap.
Normally you can move the suspension while the vehicle is in the air and check for clearance, or you'll just hear it knocking over bumps or when on full lock etc