Depends on your landlord/lady.
Estate agents will just recite the book at you
Cocks will get all pseudo legal on you and threaten to have you on the street by 9am the next day.
My landlady as a student would wait till it was 21 days overdue, then send out a polite letter asking if we'd forgoten to send it that month (we genuinely forgot, fairly regularly). Came to an agreement with her that I'd pay 3x a year to coencide with the student loans, so most of it was early by several months and a proportion was obviously late by about a month which suited us both fine as it meant I never had money wories and she had the money earning interest nicely.
Some landlords are nice and do it in a nice friendly manner, others are c***s of the highest order. Oddly, they dont seem to be on a spectrum, theyr either crap or great.