I have a connecting flight from Heathrow but I arrive on a non-affiliated flight 10 hours earlier. I know I can check-in for my BA flight well before it actually departs but when I can drop off my baggage? Ideally, I'd like to drop-off my baggage for the BA flight then just go relax in the lounge before my flight. The other option is to sit and wait in Terminal 5 for 6 hours with my suitcase....I don't like that choice much! I checked the BA site and they have lots of info on what I can take and how much and the size, etc but I found nothing on when I can actually drop-off my bag.