What's the biggest factor for denim durability? Is it purely quality of denim? Weight? Regular washes?

Question says it all. I've read and experienced conflicting ideas on what makes your jeans last.

I have had APC New Cure's and New Standards which both fell apart around the year mark - crotches were pretty destroyed. Unwearable now.

RRL Slim Fits which fared a little better, but around 1 year mark, had to repair crotch blowout. Still going strong after 2+ years but some rips along thigh and knees now.

Somet 030's at 13.8oz my lightest jean and I haven't had a major crotch blowout after 1.5 years, but have had to send them in for some minor crotch repairs. My favorite jeans thus far in fit and quality.

I plan on getting some 3sixteen's or Iron Hearts @ 17-19oz next but wonder if the heavier denim will last that much longer since my experience has been my lightest jean lasting me the longest. I know that crotch blowout and wear and tear is inevitable, but i'd rather not have to take my jeans to Denim Therapy/Self-Edge every 4-6 months.

Thanks in advance.