There is also the future to consider if any repair made fails at a future date...Replacement covers won't be so common then..
As an aside I have found than many internal threads get damaged simply because they are clagged up with sealant, oil and grease deposits, bits of gasket, paint deposits etc.etc...and that's apart from the fact they frequently have damaged fasteners forced into them...
That makes any taps and dies that are bought a good investment...When rebuilding bikes I routinely tap out all the threads and inspect the threads on any reused fasteners very carefully prior to fitting...If it's tight to screw in when fitting there's something wrong with one of the threads!
Though the taps and dies required are many, covering different sizes and threads, they can be acquired gradually over time to spread the costs...Ian
