Well I'm 42 years old. I would think my resources are at least marginally better than a youngster like yourself!
How long I wait between mods depends on resources, need/want and what kinda trail is planned. When you plan a long trip like the Rubicon or Dusy, everybody just seems to be scrambling for something they just can't do without. When going to the Dusy for instance, none of my buddies with onboard welders were going. Well that's a long hardcore ride and I didn't want to be out in the middle of nowhere and none of us have a welder, so I bought one.
Believe me, there's still so many things I'd still like to put into this Jeep. It's incredible how much you can just keep improving these things. I'm really in a quandry about an engine swap. I'd love the power of a V8. But I can't imagine an engine more reliable then the 4.0. I want performance, but I don't want to sacrifice reliability getting it. The 5.9 liter was high on my list until some experts informed me of a few quirks with that engine. There's other stuff I "need" too! Like corner guards. Can ya believe after all I've done to this thing I don't have corner guards? I just haven't dinged up my corners is all. I want bigger tires now. My 35s don't get them big 60s off the ground much. I want Kilby's onboard air system. I have a good one, but his is the best. I like buying the best. And get this, my wife encourages this. Go figure!
I bought the Jeep new in Sept of 94. A Sahara cause, it's the best. I've basically built it a few times over. I've been through 3.5", 4", SOA w/stock springs, SOA w/custom springs. I had my stock axles loaded with 4.10s and ARBs and the tcase with the MIT SYE.
Last year I did kinda get crazy and dumped a whopping amount of cash into this Jeep. I basically bought a brand new drivetrain. Custom axles from Dynatrac, a new NV4500 and Atlas from Advanced. That stuff is not by any means cheap, but it's the best. Add into that custom springs, new tires and rims.
If I had just bought the Jeep, then put the setup I have now in it, just think how much money I would have saved! I don't feel bad about the previous investments though because my less fortunate friends and my son happily take my leftovers. My son has a pretty well setup Jeep as a result. Matter of fact, I'd say that for many here, he probably has a pretty envious setup. His Jeep is running the 4.0,AX15,NP231 w/SYE, Terra 4:1 and stock axles with 4.10s and ARBs. He's like 70:1 which ain't bad at all. He's been telling me my winch needs replacing. I think he's pulling my leg though!
Hey, I'm honestly glad I didn't get into this Jeep thing till I got older. Every resource I had went into raising kids. Unless you have a family, you can't imagine how expensive it is. There's no way I could have afforded to even make the trips, much less afford the modifications it takes to rockcrawl.
All I can suggest is start a savings plan and be patient. Don't buy crap cause it doesn't save you any money when you have to buy it again.