In message , at 09:56:08 on Fri, 10 Oct
2014, Mizter T remarked:

Auto top-up is a bit of a faff to set up, and cancelling it (should one
wish to) needs you to do the same as setting it up - nominate a station
and make a journey starting or ending there within the next 8 (I think)
days.

Also I think it's possible to end up in a bit of a pickle should one
get a new debit/credit card having had the previous one lost or stolen,
and not update TfL with the details of the new one - if you use the
Oyster and it gets auto topped-up, and thus owe TfL money, they're very
keen on you giving them the new credit/debit card details pronto
(within 3 days I think), else they'll hotlist the Oyster card (which
results in it being permanently nuked if an attempt is made to use it).

And if you got a new Barclays OnePulse card (even a routine replacement)
that had a different Oyster Card number, so you had to ring them up to
transfer the balance and the auto-topup, but I don't think you had to
re-active the auto-topup. All ancient history now of course.
--
Roland Perry