So, I bought used lens. What should I inspect?

[Vladyxa]

Thanks to all good people on this forum, I learned to voices of wisdom and bought used 80-200 lens?

The seller I bought it from says it was looked at by camera shop for service before the sale to make sure it was in perfect condition. Aperture ring was tight, so they replaced it.

I have no reasons not to believe him.
But one time I asked another seller why the lens was brought for cleaning, he responded that lens had mold, and required cleaning.

Thank you.

 

[KmH]

Put it on your camera and make some images using a variety of focal lengths and apertures.

Upload the images to your computer and look them over.