Clean hands when you handle them.
Clean storage of your IEMs when not in use.
Do not roll them before putting them in your ears.
Have clean ears.
And many more, I am sure can affect the life span of any tips
Shure Olives and Ety Tri-Flange. Also, I liked the Klipsch Dual-Flange tips as well. My ears like multiple flange tips, some (apparently most?) don't. I never liked foam tips, just like the way I don't like Velour pads on Headphones.
The best tips for what? There are just no universal tips that are best for every iem. I've tried everything. While the shure olives are great for some iems and one of my favorites for a lonf time, but they are just not the best for every iem. Some iems just sound good with meelec dual-flanges, others with ety tri-flanges, sony hybrids and so on. Sooner or later one has to deal with the reality and get a decent collection of different tips.