I hear periodically about people having problems with wheel bearings on Rangers but I am still on the original bearing with over 148,000 miles. They show no signs of being worn and the truck has served its share of off-road duty. So, I don't think it could be considered a common failure.
Ball joints are another thing that some people have a problem with but I am still on my originals. Although, I do think they are approaching the point of needing replacement. The boots on the upper ball joints have cracked. I pumped a little more grease in them and sealed with silicone. That should extend their life a few more miles.
2002 FX4 Bright Red Supercab 4.0 SOHC, manual 5-spd & Tcase, 33" BFG MTs, K&N air filter, Modified air box inlet, Gibson SS cat. back exhaust, Bama flash, Hidden Hitch round receiver, Rear helper air springs, Electric trailer brake controller, Line-X bed liner, WAAG bar with KC lights and Wildernest shell.