If the engine has been maintained well, it should last for another 100,000 miles or so. The Air conditioner compressor may start leaking if it has not been replaced. Mine went out after 7 years. You should expect a few parts will wear out and need replacing but it should not be major (like the engine or tranny). I always recommend taking the jeep to a mechanic that you trust and have him/her look it over to make sure everything is OK.
Good Luck and happy jeepin'
2000 Jeep Grand Cherokee V8 Stock
93 YJ I6 hard top (really belongs to SPEED)
RE 4.5" Extreme Duty Lift, Advanced Adapters SYE, Tom Woods CV Drive Shaft, EA589 10" rims with 33" x 12.5" MT/Rs
Bullet Proof Front and Rear Bumpers and Tow bar