# Rent Increases (Substantive) > Verify annual guideline % and RTB-7 (or current form) on RTB site each year. ## Valid increase (working) 1. Written notice — **3 full calendar months** 2. Correct form 3. ≤ Rent Increase Guideline 4. Not more than once per **12 months** 5. Proper service (ss. 88–89) ## Tenant challenge window Often **30 days** from receipt of notice — **`[VERIFY]`**. File RTB dispute. ## Above-guideline Landlord applies under the Act (often s. 44 family). Tenant: - Files Response - Attends - Demands capital expenditure / financial disclosure ## Evidence - [ ] Notice document + envelope/service proof - [ ] Prior increase date - [ ] Calculation vs guideline - [ ] Rent ledger