It will not expire unless you'll leave UK for 2 years or so.
Also if you want to apply for British Citizenship in the future, you should not be away for more than 90 days a year in the UK.(well the other forum members can correct this if I'm wrong..)
A follow up question though, hmmm is it true that we need to wait for 5 years before applying for Citizenship or is it still for 3 years stay here in the UK? I read a link here in the forum about that proposal --5 years before Citizenship
.( can't remember what thread it was though)
Thank you all--Best of luck to all of us!!!Cheers!!!![]()