Don't really know I just keep it above 3000rpm where it is supposed to be

Normally 2nd/3rd for me. If I'm in 4th I've obviously forgotten to change down to 3rd. I might leave it in 2nd if I know I'm going to be slowing down again in a couple of hundred yards or so.

But then I like engine braking, it's very rare that I use the brakes for anything other than stopping. I even tried doing the whole of my 22 mile commute along A/B roads in third gear one day the other week when I had a sore toe, it was fine for anything between 20 and 90!