Trying to correct someones screw up usually takes twice to three times longer, rather than them bringing it to me first. I try to be fair with fellow enthusiasts, but sometimes they really try my patience and I've lost a few due to labor costs.
If they bring it to my shop, I will fix it for free if I can do
it in less than an hour for no charge given they leave
it for a few days until I can find the time.
Beyond that, I will give them my opinion, but I will not
put my hands on it! If they argue with me about my
advise (common) that will be the last time they receive
any from me.
At 75 year old, I have come to the realization that I have more
money than I have time at this point. I have lost patience with
time wasters and folks that grind me to death on the price of something!