it is UP TO 1000. the phase change pretty much makes the reflectivity useless after a while. depending on use and age, dont expect remotely close to 100 though. and the 1000 includes any changes to the CDRW. so if you write, it's once. if you format, it's once. if you erase, it's once. so if you format it for packet writing, then erase it, it's 2 writes. and the writing is also a write. if you burn it as a normal cd, it's a write. if you erase that it's another write.