is it true that both rewritable cds and dvds can be rewritten 1000 times?
No. The real number is somewhere between 1 and a few hundred, depending on the particular media and the drive.
how many times can you read/access a burned cdr and dvd discs
Same answer. Nobody really knows. The real limiting factor has more to do with how the discs are handled and stored.
Does a cd last longer then dvd and is there difference between + and - and whether it's rewritable media or not
No, and no, and RW media is far less reliable than R.