Dave Plowman (News) wrote:

Oyster is PAYG. You can get a one
day travel card that gives unlimited travel. However, it looks like PAYG
with capping may be the best of all.

I thought TFL would charge you the lesser of the sum of individual
journeys you made, or a one day travelcard that encompassed the zones
you'd been in? Hence the recommendation to use the same contactless
card for all journeys.