Your chance, OVER TIME, is increased as odds say eventually you will hit the schematic. However each individual roll is 20% regardless of anything that has every happened before it.
Not really. It's unlikely you'll go on a long streak of failures, but just because you HAVE gone on a long streak of failures in no way impacts the odds of future success.
Here's a depressing thought for all you crafters. For those 10% success items, the odds of getting a success on your next attempt (10%) is just about the same as the odds your next attempt will be the first
in a string of 22 failures. (9.8%)
Each and every time you RE. Depressed much?
edit: and P.S. My suggestion is whenever possible, never try to RE a single item at a time. Set up 5 *different* items in your crafting queue(s), so you aren't wasting mats if you happen to get the RE after the first one... and so you aren't wasting time changing characters so often by only having 1 item in the queue. Only when you're down to very few worthwhile schematics left to learn should you be either doing multiples of 1, or only having 1 item in the queue.