Please advise: Extend the lease for 3 months or find a new tenan

My tenants signed a lease last year for 9 months and they just asked for a 3-month extension on the lease to end of August this year. I am thinking just to give them the extension. However, I am extremely new to this. Every decision is a new one for me. I want to get opinions from the experiened landlords here to see whether this is ok. Thanks in advance!