Jack - fair enough. I don't often get nervous about pitching - once I've got a song down my voice seems to remember what note to start on - and if I ever do I've usually got a whistle to hand. But whatever works!

I do drift sometimes, particularly on long songs - the first time I recorded myself singing Lord Bateman I discovered when I listened to it back that I'd been a full tone lower at the end than when I'd started. I think that's the only exception to the general rule of musicianly self-awareness: If You're Screwing Up You're The First To Know (If You're Any Good). Does drifting matter, though? I'd say not much, if you're singing unaccompanied - just as long as it is a drift & not a sudden lurch, and as long as you don't drift so low (or high) as to give yourself problems.