Maybe you do this already, but when you're done, DRY the razor off THOROUGHLY before you put it back; don't just let it air-dry. Easy thing to overlook. The blade will stay sharp longer. Of course, if the blade is sharper you won't have to press as hard and you'll have less irritation.
I used to use the non-disposable kind (Gillete Sens-a-trec or something like that) until my local Acme started putting these little red things on the end of each prong of the razor blade display to prevent customers from just pulling them off like any normal item. So if you wanted to buy one of those razors, you had to find a salesperson to assist you. For razor blades. I guess the reason Acme's parent company's revenues were down $52 million last quarter is because people kept stealing shaving items. So they added this "security" feature. That's when I discovered disposables lasted just as long, did just as good a job, and were a hell of a lot cheaper.