janisj

For 1 to 4-ish days = PAYG

But for 4.5 or more days, a 7-day travelcard is usually the best option. Of course there are exceptions - for instance if one doesn't use the tube much and walks everywhere.

My typical break even point on a 7-day travelcard is the morning of my 5th day in town.

jamikins

Ditto to what janisj says. Sure, there are exceptions...the individual traveller will have to do the math based on their own usage, but janisj gives the same general guidelines I do.

My parents just pay the single ticket to central London on arrival and departure...the few extra £££ they make up on the 2for1s. Not a hassle at all.

If you go outside zone 1-2 then go to the ticket counter and tell them about your ticket and they will tell you what you need. I think these are rare exceptions...most stay within zone 1-2.

Or get an oyster and put some cash to cover the heathrow and outside zone 1-2.

People over think this and beat it to death. At the end of the day if you spend an extra £5 getting somewhere that's a small portion of your trip. Do the math, make the best decisions for you...