Pre-owned hot tubs come with advantages and risks. Many reputable dealers offer refurbished units that have been thoroughly cleaned, tuned up and double-checked for flaws. The warranty on a pre-owned spa varies, and is inevitably shorter than the warranty on a new spa.
The clear advantage to a used hot tub is the lower price. The disadvantage is that the spa’s early life has already been consumed, so you may not get as many years of use out of a second-hand hot tub as a new one.
Like a car, the life of a hot tub largely depends on how well it is cared for.