I check the fittings every morning on my ride THAT HAS FULL FENDERS I have secured all fittings with stainless brackets and use locktite on all my nylock fittings aswell I have secured every bolt with small rubber washers to prevent vibration and only once have I had an issue BEFORE I FITTED ALL OF THESE MEASURES ,since I've never had any issues ,it's all about checking and double checking ,every ride I take the fender in my hand and give it a good tug and twist , they havnt moved in over 1000 miles
Still I will call it a gamble though ,but as long as the checks are done properly and all checks pass the chances are minimal ,besides that I'm more likely to be killed or hurt from an irresponsible driver ( of which 9 out of 10 here are ) .
IMHO cracking or breaking fenders or any part of a chinagirl kit is due to a lack of checking for faults and not bothering to correctly identify an issue .
Run your fingers over your frame or a joint ,you may not see a hairline fracture but you will feel it ,every few weeks remove the fender and check for potential damage or failure ,tighten every fitting and then check it ,and recheck it , look at potential areas with an attitude like it's going to fail and treat it as such ,yes it may be time consuming but what is that time worth ? Your safety and well being .
I am one of thos e who is pedantic about checking Christ I'd almost consider myself OCD , yes I have had near failures but have stepped in and secured the problem before it became an accident .
Regards Hen