I've accidently done the 2 blade thing - but I think holding the thing wrong doesn't help. I use a TrueCut. I took the guide out and use it as a regular rotary. It will cut fine, start skipping, then cut really well again. I should think if the blade was bad, the skips would be consistent, but no. So I don't like to change until I figure out what is going on - whether it's me or the blade.