As you have already noticed, rental gear will not kill you. I don't dive much more often than you but I decided to buy my gear. I shopped closeouts, demos, etc. and got great deals on decent gear, but it still doesn't make sense financially. The only way I can justify it is because I simply like having my own stuff. It's worth a few extra dollars to me. I put my gear together quickly and easily on the boat and even an unfamiliar divemaster leaves me alone and focuses on the others. I know how much weight to put in each pocket. Underwater, I know where my computer is clipped, where my dump valves are, how a quick shot of air will affect my BC, and what strap to pull if it's rubbing my left shoulder, all without having to experiment. Back on the boat I know the easiest way to swap tanks for the second dive or to break down my gear and have it stowed before the boat starts moving. At the dock I know how best to rinse my gear and stow it in my bag quickly. In short, using the same gear every time saves you time and effort. Time is my most valuable commodity when I'm travelling so that makes it worth the money to me.