Ok I fish south Texas- Falcon lake. Lots of timber and rock. I have had most success on a 5xd. I have been using sunline sniper 12lbs. I like it but I bought a spool of 15lbs at a 1000yds invisx from TW sale. I am tempted to try it, but don't want to waste it. I have other rods I'm gonna use it on. I am torn on line size. I want to try and crank deeper but I don't want to go too light. I was losing enough lures as it was with 12lbs from trees. From those of you who have more experience what would you do? Is the depth difference between 12 and 15lbs test that much? I fish out of a kayak if that has any bearing on your advice. I also plan to throw 8xd and similar eventually. Target 20-25 fow. Thanks

I don´t sound like an arse hole but, instead of thinking about changing your line you should be thinking about getting a lure retriever. You fish Falcon, I fish La Sauceda and it looks like this:

It´s been decades since I lost a crank and I sometimes fish in that mesquite and willow tree jungle with line as light as 8 lb.

I have a lure retriever. I haven't lost a bait since I got it. Haven't needed to use it either. I like the option pulling without worrying about the line snapping. Have you have any trouble landing bigger bass in the timber with line smaller than 12lbs. I also actually need to change it. I'm almost to the spoil when I cast. I don't have a lot of experience bass fishing as much as I do for redfish so light line has me hesitant. 

14 minutes ago, GetBent said:

I have a lure retriever. I haven't lost a bait since I got it. Haven't needed to use it either. I like the option pulling without worrying about the line snapping. Have you have any trouble landing bigger bass in the timber with line smaller than 12lbs. I also actually need to change it. I'm almost to the spoil when I cast. I don't have a lot of experience bass fishing as much as I do for redfish so light line has me hesitant. 

Heavier line kills the action of many baits like lipped cranks, heavier you go less "life like" action your bait has, so that would end up in less bites just because you want the option of pulling without worrying about the line snapping.

No, I don´t have any trouble landing bigger bass in the timber with one smaller than 12 lbs, that´s why I tell you that many with many baits I go as light as 8 lbs, I could go with line as light as 6 lb, the only problem with line that light is that the abrasion resistance diminishes greatly and you know how rough mesquite is.

If 12 lb line gets your lure to where the fish are then keep using it. You may lose a few ft of depth using 15 lb. But you could always use the "kneel and reel" technique by sticking the rod tip in the water to help with that.