Good- we're getting close to an answer to the whole question of tenants breaking a lease. Something that no poster so far has given a clear defintive legal answer.
It's simple enough - Knuttell has provided most if not all of the answers.
If there is no lease, or if a lease has lapsed and the tenancy is then Part IV, then the RTA periods of notice apply.
If there
is a fixed term lease, then assuming there are no break clauses, then the tenant cannot just decide to leave midway through, nor can the landlord decide he wants the dwelling back because he wants to sell etc. A fixed term is a fixed term.
The only way out for a tenant is to find someone willing to sublet, to whom they can assign the remainder of the lease. This isn't a general, common sense thing, the right to assign the lease is actually provided for in the legislation. If the tenant requests permission to assign the lease to someone and the landlord refuses then the tenant can serve notice of termination and they are entitled to their deposit back.
I'm not sure why a tenant would sign a new lease which really only assures him that the landlord won't evict him even on the grounds allowed by Part IV (needing house for family, etc) but costs the tenant his right to terminate the lease with appropriate notice.
Simple - if you want true security of tenure as a tenant then you
need a fixed term lease. What use is the RTA "security of tenure"? Under it you're out if:
The landlord wants to sell.
The landlord wants the house for himself or a family member.
The landlord wants to alter the purpose of the property.
among others. The RTA itself gives no real security of tenure to tenants, because if a landlord wants to end the tenancy he has a range of options open to him. In any case, wanting to sell and wanting the house for personal or family use are probably the two main reasons a landlord would want the dwelling back, and the RTA caters well for them in this respect.
If you as a tenant are flexible, and like the idea of being able to move at fairly short notice, then Part IV may be a good idea. But you need to be aware that it affords the landlord flexibility also.
There is general ignorance of obligations and entitlements from both landlords and tenants in Ireland, an educational campaign is well overdue. Tenants and landlords witholding rents/deposits because they don't understand the law isn't doing the renting sector any good at all.