I seem to be patching jeans constantly. I keep a bag of patches of every colour of denim. I cut the patch about a half inch larger than the hole, round the corners and applique it right over the hole using a fairly dense zig-zag in a matching thread. My patches are often round or oval and they seem to wear well. Patching on top lasts longer and looks better than trying to put the patch underneath. I have the older Bernina 830 and it has an open arm which means you don't have to open any seams. My husband spilt battery acid down the leg of his brand new jeans leaving quarter sized holes. I patched every one (9 I think) and the lady at the bank told him someone must really love him to take the time to patch all those holes!