Yep and yep 
The good news, you can rebuild them 
Bass (and some midrange) drivers sag with age sometimes causing the coil to rub on the pole. Rotate them.
Roll surrounds perish. You can replace them.
Spiders sag and the glue degrades with time.
The limitation in repairs is usually not being able to get the bits.
Fact is, you can’t go far wrong if you treat speakers the same way you should treat a mature women; they both sag over time and go off tune.
Really you need to flip em over regularly, don’t cane them too hard, replace their electronics from time to time and you should get delightfully high squeals and low moans out of them for years.
Worst case scenario might require a few cosmetic repairs, or try hanging them upside down for a bit.
Last edited by Welder; 07-12-2010 at 12:30.
Single spur balanced Mains. Self built music server with 3 seperate linear PSU, Intel i5, 16 GB RAM no hard drive (various Linux OS). Benchmark Dac2 HGC, single ended XLR interconnects/Belkin cable. Exposure 21RC Pre, Super 18 Power (recap & modified). Modded World Audio HD83 HP amp. Hand built Monitors with external crossovers , Volt 250 bass & ABR, Scanspeak 13M8621 Mid & Scanspeak D2905/9300 Hi. HD595 & Beyer 880 (600 ohm) cans.
The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts.
-Bertrand Russel
John.