Lufkin red end rulers have been my mainstay in measuring since the early 80's. The single brass extension is the #X46, and you're lucky you can find a double brass slide #X46X that has a brass extension on each end; Lufkin stopped making those several years ago. They also make an 8' version #X48. I don't have any real tricks or tips that have not been mentioned, just take careful care of them. Like Rob said, carrying them around in your back pocket is handy, but wears the paint and numbers off, not to mention what sitting on them does for the integrity and accuracy. I carry mine in the side pocket of my fatigues. Always keep them dry. I've always just used 3-in-1 oil on the joints, although like Rob said, parafin, wax or even graphite would collect less dust and trash. The only tip I may have is keep them away from kids, while growing up my boys probably broke 20 folding rules for me.