WARNING: long reply ahead.
Whenever I do repairs myself, or have them done by the shop, I try and think of it in terms of "payments" as if you had a vehicle the was 4 years old (out of warranty), yet you were still making payments. Given the high prices of new cars today, say at least $25K for a new vehicle, taking care of an older vehicle can seem appealing, especially when you own the vehicle and can do a lot of the maintenance work yourself. So payments nowadays are at least $350 for newer vehicles, give or take, and many people finance for 5 years. Given the model years discussed in this forum, I guess many here own their Jeeps outright. So by my rational, a $700 repair bill really only is equal to two months "payments" on a newer vehicle. And we are all aware of how much you save by doing repairs yourself.
Now, how long can you Jeep last? I say indefinitely...as long as you can find parts, and afford to have the work done, either by yourself or somebody else. Heck, I saw a new engine advertised for approx $800. Also, when I calculate how much I spend on repairs (trying to keep in mind that ever begging question "is it worth it?"), I don't necessarily include "normal" upkeep, i.e., tires, plugs, oil, etc., because you would have those repairs and replacements with any newer vehicle. I know BMW and Audi offer free maintenance for the first few years of ownership...but that's mostly a marketing ploy. I mean, how much is there to do in the first four years of a car's life? Usually, not much. Furthermore, most people accept the fact that a new car is the biggest loss of money out there, but they do it because of various reasons, i.e., dependability, status, etc. To each his own. The only way to even come close to getting your money out of a vehicle is to do what people do here, get advice from others and perform repairs themselves. I've saved a lot of money by the things I've learned from this forum. For instance, I just replace a blower resistor that cost me $20. To have it installed by the shop would have cost me at least $80.
Now, a lot of this response may seem like a lot of financial mumbo jumbo, but when you look at your "investement" into a vehicle, these are the things you have to consider, not only if the vehicle will run. You can keep it running for virtually ever. Look at those guys who restore vehicles from the '30s.
I have a '92 Cherokee with 159, 000 that I bought as a winter driver...but I have to admit, I've become attached to the thing and find myself wondering how long it will last...and then I put more $ into it whenever it needs it. You know you're banking on it when you buy four new tires for a vehicle with 159K, lol. I like driving it more sometimes than my 03 Dakota in the garage. I guess I've been bitten by the Jeep bug.