When do know it's time to change your hook on a TX rig, besides starting to miss some fish? Is there a certain number of fish caught? For instance, change after 10 catches?

When its not sharp anymore.... 

I retie the hook to the line if the knot and line start getting some nicks in them. I use the same hook unless it gets bent from snagging it on something. If your hooks are getting dull you can pick up a hook sharpening file from BPS. I keep one of those in my tackle bag.

drag the hook tip across your fingernail it doesn't leave a scratch of grab your nail replace it.

When I lose them on a snag.

Catching bass doesn't dull the hook point, it may fray the line. Hook points are damaged by sticking something that is hard like a rock or something similar. Today's hardened tempered hooks are difficult to sharpen on the water, you are better off changing to a new hook if the point is flattened or dull. Honning the hook point at home is a better idea, unless it's the last hook you have with you.

Your thumb nail works good to check how sharp the point is by dragging it across lightly to see if it leaves a scratch. Test a new hook to get the idea of how a sharp point should feel.

I check all my hooks often for sharpness and my line more often for any abrasions and retie often, otherwise you may regrete not doing this.

Tom

If I roll a point or it doesn't feel sharp anymore then I'll change it.