Is it good for a Krell to SIT for 3-5yrs

I have been told that the worst thing you can do is let a big Krell sit in its box for years.I was told the caps all dry out especially if it has not been serviced for 10yrs.I am looking for a KSA 300s but they are all just sitting in the closet then coming out for Big Bucks.Is this not bad for them?