A protein skimmer can last for many years. It is acrylic, and can always be soaked to clean it up like new again. I was probably the fourth owner of an Aqua-C EV-200, which after a couple of years I sold to another club member. As long as it hasn't been dropped, isn't cracked or leaking out of the box, the seams, or the joints, it should be fine.
That type of skimmer uses a Clover-leaf injector. You will need to inspect it and clean it the first time, and then every 60 to 90 days you need to verify it is still clean. The pump may need to be replaced, but that's not a big deal. It's a good skimmer, & a good brand.
