A Part 4 tenancy generally arises after you have rented a property continuously for six months without receiving a valid notice ending the tenancy. It gives you greater security of tenure, meaning your landlord can usually end the tenancy only for a reason allowed by the Residential Tenancies Acts and by following the correct notice rules. A fixed-term lease does not usually remove these statutory protections, although the agreement and any breach can still matter. Tenancies that began on or after 11 June 2022 are generally described as tenancies of unlimited duration, so check the current guidance on the RTB website for the rules applying to your tenancy.