Work/Study during 10 year Legal Stay?

[guruasis2012]

Hi,
I am not very familiar with this route. Can someone tell me if I shall be eligible for it. I was on T1 General for 4 year 11 months but because I couldn't easily meet the salary criteria for T1 extension (which is same for 5year ILR), I am contemplating of switching to Tier 4 for studies, in my case MPhil/PhD. My question is whether I have to keep all original documents (P60s, Payslips etc) of all work (full time during T1 and part time during T4) I have/will do during ALL 10 years to apply for ILR? Is ones passport the only way to prove 10 year continuous stay (including less than 6-month breaks)?
Thanks a lot.