capable of being adjusted

adjustable seat belts.

(of loans, mortgages, etc.) having a flexible rate, as one based on money market interest rates or on the rate of inflation or cost of living.

(esp. of life insurance) having flexible premiums and coverage, based on the insuree's current needs and ability to pay.

any rate, expense, income, etc., that varies unpredictably

Luckily, his chief income is not made up of adjustables. Allow some money in your budget for the adjustables.

adjective

accommodating , adaptable , changeable , conformable , flexible , malleable , modifiable , pliable , tractable , adaptive , elastic , pliant , supple