If you have a lease for a certain period of time (not month-to-month) your landlord cannot ordinarily increase the rent during that time. Many leases are for 12 months, so the rent is adjusted at that time after the lease ends.

Many managed apartment complexes are going to 'fluid pricing' where a number of factors -time of year, local market, etc will determine pricing so advertised rent costs may either rise, stay the same, or fall depending on those factors.

Thanks, Lucille--I shared this info with my friend, who is on a month-to-month. She's never had a rent decrease--that seems to be the stuff of seeing a unicorn!

Look at the tenant/landlord rules in your jurisdiction. In my county, rent can only be increased once a year, even when on a month-to-month basis. Also, there are guidelines on annual rent increase (percent) and the requirement to justify an increase.

Alternatively, your friend could ask for a longer lease and/or ask the landlord for a lower increase. If s/he is a good tenant, and unless the landlord wants to get rid of him/her, the landlord may want to work with her/him.