The answer surely is to buy a breathaliser and keep it beside your bed. Wake up in the morning have a blow, if it registers phone up crewing report "unfit" and the go back to sleep.
Seriously though the problem that we have is that without a breathaliser you have no way of knowing how fast alchohol has been removed from your bloodstream. There is an article in today's Daily Telegraph; they cost £25. Cheap "loss of licence" insurance