Can my landlord raise the rent whenever they want?

Not during a fixed-term lease. If you signed a 12-month lease at a stated rent, that number is contractually locked until the term ends, unless the lease itself contains an escalation clause you agreed to. The raise conversation happens at renewal, or anytime for month-to-month tenants, subject to written notice, commonly 30 days, often 60 or 90 for larger increases or longer tenancies, depending on the state.

How high they can go depends entirely on where you live. Most of the country has no cap: the market is the limit. But rent-stabilized units in New York, rent-controlled jurisdictions in California (statewide capped at 5 percent plus inflation, maximum 10 percent, under AB 1482), Oregon's statewide cap, and various city ordinances all restrict increases, so check your city and state before assuming either answer.

Two universal protections: a raise cannot be retaliation for complaining about conditions or exercising legal rights, and it cannot be discriminatory under the Fair Housing Act. Document everything in writing; your state attorney general or local tenant union can tell you the exact local rules.