Why make such a big deal out of checking your purse every time? That just sounds like extra work for no real reason. One lost wallet does not mean you need to change how you do things forever. Overthinking it can make you more tense when you actually do forget something. Stuff gets lost sometimes, that's just how life goes. Fix the problem when it happens instead of wasting time on pointless checks.
Try building the purse check into your leaving routine so it becomes automatic, dude. @kim373, that "one lost wallet" feeling of panic is why I do it now. Takes two seconds and saves a huge headache later.