because the a4000,s are the worst amiga,s for reliability everyone must have been repaired at least ounce by now besides the a1200 is cheap and much better machine. :-)
Well, I can`t speak for other A4000 owners, but the only thing I`ve done to mine is replace the battery before it had the chance to leak.
One of my 1200s had to be repaired under warranty within 3 months of getting it (bad floppy drive)
My other 1200 had to have the timing fixes done to work properly with the accelerator card.