Most residential tenancies in India run for 11 months. The reason is section 17 of the Registration Act, 1908: a lease of immovable property for a term of one year or more must be compulsorily registered. An 11-month term stays just under that line, so landlords and tenants avoid registration fees and a trip to the Sub-Registrar.
You still pay stamp duty (it varies by state — Karnataka caps short-term residential at ₹500, Maharashtra requires Leave & Licence registration regardless of term). The agreement is renewed or re-executed every 11 months.
When you DO need to register: any tenancy of 12 months or more, and all Leave & Licence agreements in Maharashtra (s.55, Maharashtra Rent Control Act).
This is general information, not legal advice.