Evidence for PR application

[Pigkappa]

I am an EU citizen in Britain and would like to apply for a PR document as soon as possible, in about 18 months. Until a month ago I had no idea how difficult it would be, but now I understand that good evidence is required. I apologize for the many questions. I want to say thank you to all of you as the help you often give here is amazing and I learnt a lot reading this forum.

I discovered I need to keep track of each time I entered/exited the UK. I managed to do so and already have 30 such instances. Does one need to provide evidence for this? Most times my passport wasn't stamped as the travel was in the EU. I probably did not keep confirmation emails for each of these trips. What evidence do people usually provide?

I have been advised to have 2 pieces of evidence for each address. Unfortunately for each of the last three years I do not:
1) University accommodation (no bills, no council tax, only bank statement),
2) Shared house with students (bills not in my name, I do have the rental contract, still the college address for the bank),
3) Living with my girlfriend (my name was not on the contract, bills in her name - but I moved the address of my bank account to the house so I have a bank statement).

I also have done some work for my department on the side while I was a student. I never had to pay any tax (at most I was paid ~£1000 per year); my main scholarship is tax-free. So I stupidly didn't bother to collect or keep all forms like P60s/P45s (I am not even sure what they are exactly). Is it a problem? My time as a student does count because I have a European Health Card, but I wonder if it's important to document any work done.

I'll be more careful from now but can't change the past. Would what I have for now be enough?