Nope. I'm on a very simple PAYG sim-only monthly top-up plan. Pay £15* each month, and as a 'bonus' you get unlimited texts and internet. That £15 goes onto my credit balance each month, and as I rarely make calls, it just goes up and up.
*They have a £10 / month plan now I think.
Advantages:
- Cheap.
- My credit balance is skyhigh.
Disadvantages:
- I have to top up £15 every month. They always text me a few days in advance, and I can do it online or at a cash machine - takes a few seconds.
- After each text I get a balance notification from 02. Sometimes it's handy, sometimes it's annoying.