If I spot a glaring mistake in a recent episode, I'll often go back and make quick touch ups in an editing pass- comic pages/episodes take so long that sometimes you just miss small stuff after staring at it for so long 
But as far as going back and reworking or redoing older episodes after some time has passed? Nahhh. I've fallen down the slippery slope that is the redo loop when I was younger. I found that typically it takes way more time and effort to go back and do that kind of rework relative to the value that you get out of it.
Also like, where do you stop? If you touch up chapter 1 out of 10, for example, chapter 2 might look a little meh/off by comparison since it's also older. If you do chapters 1 and 2, then 3 has the same issue... and so on. So do you do the whole thing? Do you just accept that there will be a random drop in quality and bank on the early stuff being good enough to retain readers through that? idk.
That said, I'm also a big fan of seeing improvement over time! I think there's something endearing about that and it's always a little sad when that is lost by overwritten edits :')