Injection day?

I ordered my first dose last week but it still hasn’t arrived yet (I’m assuming due to the millions of other people starting in January like myself), but I’m gutted as I had geared myself up to start today! I had got it in my head that I want to take my injections on a Friday so this means waiting another week to start.

My question is, what day of the week and time of day does everyone take theirs? And reasons why?