Yes, according to EE's PAYG price guide, at least once every 180 days you need to do one of the following:

• Making a chargeable outbound call
• Sending a text message
• Topping up your account
• Making a payment for an Add-On
• Registering your details

I still have one spare nano-SIM (which possibly has £5 free credit on it) and two spare combin-SIMs (which probably don't have any free credit on them).

Thank you for your reply NFH. ;)

Another question: what types of voucher can I use to top up an EE sim? I mean, if I got a T-Mobile voucher, could I use that to top-up an EE PAYG sim?

Alternatively... could I use a Neteller prepaid card to top-up a UK number? Otherwise I'll buy one or two spare vouchers next time (really soon) I get in the UK :D

I don't think that Orange and T-Mobile vouchers are interchangeable (they come in different denominations), so I'm guessing that EE is different too. EE PAYG is still so new that their staff often don't know the answers to such questions anyway.

...and on their website, vouchers aren't mentioned as a top up method, nor cash machines (I don't even know if foreign cards are allowed to top up at ATMs...). So I guess I'll be able to only top up by swipe card. What a strange carrier is EE :D

So I've discovered that you can top-up EE prepaid sims with eVouchers. Just text 150 "VO" plus your voucher code, e.g. VO0123456789123456 ;)

It's curious that the voucher I was given at WHSmith was for "EE Mobile Broadband" (PAYG obviously) and not generic "Pay As You Go", but apparently it doesn't matter. :)

EE seems disjointed in what you can and cannot do with their vouchers. I use PAYG EE 6GB SIM cards but have learned to use them and throw them :)