A move-in inspection is the record you will wish you had at move-out. Walk every room, note the condition, and get the tenant to sign off before they move a single box in.
What to record
Walls, floors, fittings and appliances, room by room. A short note is enough - "light wear on worktop" is more useful later than no note at all.
Keep every rent date in one place.
See how Tenant HQ tracks rent, reminders and overdue accounts.