Looks way worse than it is. Clean it out and add salt. The resin should be fine, they’re rated for like 15 years. I’m sitting at 20 years with mine and it still does a fine job. In fact, by happenstance a buddy works for Culligan and he doesn’t even bring up replacement unless the unit shows actual problems keeping water soft, regardless of age.

E. Another user mentioned bacteria, which can definitely be a cause for concern if the unit was sitting for that time, but should be less of an issue if it was just used without salt and NOT on bypass. Especially considering softeners typically have a pre-filter that sits in untreated water for 4-6 months at a time and a softener doesn’t sterilize water in any way. So you’re getting same bacteria regardless.

I doubt that would be a make or break requirement for getting hired somewhere but it definitely could be the thing that differentiates you from another candidate applying for the same job. Honestly you should go ask the mechanics at your local shop for their opinion. They are usually pretty personable and the few I’ve met were very eager to help new guys get started in the trade. Could also pay off when looking for a job later if they keep you in mind.