The big three auto parts stores (AutoZone, Advance Auto Parts, and O’Reilly’s) all have tool rental programs. Basically, you buy the tool on a credit card, return it within the required window (and this varies between 24 hours and 45 days; make sure you know what it is), and they fully refund the balance to your card. If you’re short on money and they have the tool that you need, it’s a great way to lower the cost of a DIY repair.

But if you’re like me (and, admit it, you probably are), you like owning tools. You don’t want to have to run down to AutoZone, find out that they’ve already loaned out the tool, or that the bearing puller doesn’t fit your bearing. Case in point: The pilot bearing in older BMWs is very small, and most of the rented bearing pullers I’ve tried don’t fit. I’ve never had luck with the pack-it-with-bread-or-soap technique. I finally just bought the correct bearing puller and the little slide hammer it threads onto. It wasn’t terribly expensive, and I love knowing that I have it and can press it into service without wasting time hunting one down.

So, the tool calculus goes something like this: If you can afford the special tool, and you think you’ll use it more than once, and it’s available to buy and can be shipped to you in the time frame you need, OR if it’s simply not available for rental and you can stomach the cost, you buy it. But if it’s really pricey to purchase and it’s available for rental, OR if you need it right now and a local store offers it, then you rent it.

The other parameter is the cost of the tool versus paying someone else to do the job. If the tool isn’t available for rent and costs $500 to buy, but the repair is only an hour’s labor for a pro and you don’t expect to ever do it again, the economics of buying the tool probably don’t make sense (unless, of course, you just want it because it’s cool). But if the repair is impossible or onerous without the tool, and the cost of buying it is substantially less than paying someone else for the repair, then you consider buying it, even if it’s only for a single use. At least I do.