Don’t qualify in the “pro” part of your request but just fish a lot. Like was just mentioned lightly running my finger down the line usually tells me a lot. Also the minute you see kink twisting it is time to re line not retie. Also I might be wrong but when superline frays its time for me to retie… get a musky or trophy northern with a leader and the line above the leader frays a little.. 60lb breaks like 10. I have to agree though in smaller fish and in fun fishing a frayed line seems to keep catching. I rarely if ever now use superline except for tieing crawler harnesses, and as a leader on leadcore. Crawler harness is tied to mono so I have the give I need. Ofcourse the age of the line is important too.
Two sneaky wear problems that I really watch myself is the slip sinker where,( I use 6lb test for most worms), the top or mouth of the bullet rests. Everyone watches the knot end but when I stopped watching the other end I had razor sharp break offs. Looking closely at the sinker doesn’t show roughness or sharpness inside .. so it must just be rubbing wear. The worst part is it doesn’t show roughness when you run your finger on the line. You can see it though if you hold it in the sun. The second is with powder coated and also teflon coated hooks.. I’ve tried many different brands and all seem to cause serious line wear and line breakage,(again I use 6# mono a lot). The powder coat seems to be abrasive and the teflon seems to let the line slip too easily and the constant friction breaks line on the middle of the knot loop on 3# and bigger fish. I fish whenever I can with hooks that don’t have either coating ..but when I have no choice I watch it very closely.
So anything looks or feels different retie.
Regarding hook sharpening… I guess I have maybe sharpend 5 in 35 years. Usually lose them or bend then before I have to worry about the point. If a crankbait treble or single garbs rocks or snags so that now it is damaged or dull .. I just put it in the splash well,and about 4 times a year I go through and toss the ones that are bad or change the trebles if they need it. I really don’t have a hook or crankbait very long .. I lose a ton .
When I’m out for fun and not guiding or tournament fishing I do get laid back about everything above.. but I still watch .. because if you don’t some day when it matters you will get out of the habit and forget to check.