I have always used 8# or 10# line for smaller cranks in the 1/4 to 3/8 oz range and 12# line for larger cranks.

But I see the pros using 20# line for 3/8 oz cranks and wonder why so heavy? Does the weight of the line help with casting distance? Etc, etc, etc?

Your wise counsel, please.

Cover and depth normally dictate what test line I use. Baitcasting gear simply works better with larger diameter line.

If you can get away with higher # test then why not use it.

Lighter line means less memory normally. The lure will have better action, run deeper. Dont let 'pros' who water ski fish into the boat in 4 seconds be such an exaple for you and your type of fishing. Ive run 10lb mono for 1/4 cranks, I dont use heavier cranks. Ive played with 4lb mono on a Abu 1500IAR and 6lb braid on a Sol.

The thicker line helps keep the baits higher in the water column so it does not dive as deep. You can change depths by switching line diameter instead of changing lures.

I can only speak for myself. Anything that weighs less than 1/2 oz goes on my spinning rigs, whether it's a senko or a crankbait or a buzzbait; and I'll never use higher than 8 lb test (not braid of course) on my spinning reels.

I get more casting distance and cranks run deeper with a lower test line; on baitcasters or spinning. The flipside is I'll probably break off more fish with a 8 lb test than with 12 lb test, but I'm okay with that considering the advantages of lighter line. And it's not like I lose a lot of fish. I like to play them carefully, and keep them out of snags, which almost always can be done.

I hear in the Classic KVD was throwing his squarebills on 17 lb test to keep it higher in the water column. Another reason which probably hasn't been mentioned is that the pros can't afford to miss one single fish.

The pros use heavier line because they fish for a paycheck and can not risk losing a fish. I would imagine all use the heaviest line they can get away with.