@Dr. Seuss you have a year at minimum, find a couple devices that tick the most boxes for you and start watching for sales to pick up one or two more at a time. Try to to find users that have the device to see about reliability over time. The average board should give you at least 3-4 years of service though I suspect many will last much longer. PWM mods are easily repaired so maybe invest in a couple cheap ones for backups. Dovpo and Telsa have some good reasonably priced PWMs and can often be found on clearance.