Few of them have issues with valves but for as many that are out there it's not a real problem.
Many of us have way more miles than you mention and no issues , some even in to the 300-35,000 mile range. Have a buddy with an 03 and 212,000, my 04 has 186,000 uses no oil, runs as smooth today as it did when I bought it new
Regular maintenance and just getting them out and running them is the key to keeping them going.
04 Liberty, Kilimanjaro Edition, Rock Lizard RockRails/Roof Rack/Rear bumper,32 inch Goodyear Duratracs,Moabs,4.10s Matrix 4XGuard front bumper, 4.25 inch JBA Coilover lift and other goodies