I've heard two distinct opinions on reverting to your old razor when learning a straight. I've heard some say to take the plunge completely and give up your old razor. The thought being that the rough spots would be a reminder of where you need work as you dial in your technique. I've heard others say to take your straight slowly and finish your shaves with your old razor. The thought here being that the learning curve is long and why punish yourself with a scruffy face while you climb it.
Tending toward the latter, I think I've found a method that achieves both objectives, although I suspect I'm not the first to do it. I do my straight shave as best I can, which is actually getting reasonably good these days. Then I lather up one more time and do a single DE ATG pass. The areas that are smooth, I know I've got my technique down pretty well for. The areas that still cut some stubble, I know need some work. But the best part is that I shave off the stubble while I check my results. Best of both worlds.
Tending toward the latter, I think I've found a method that achieves both objectives, although I suspect I'm not the first to do it. I do my straight shave as best I can, which is actually getting reasonably good these days. Then I lather up one more time and do a single DE ATG pass. The areas that are smooth, I know I've got my technique down pretty well for. The areas that still cut some stubble, I know need some work. But the best part is that I shave off the stubble while I check my results. Best of both worlds.