How Much Surface Noise is Too Much?

Everyone's tolerance level for surface noise differs, let alone the difficulty of quantifying surface noise, so it's really an impossible question to answer, IMO.

If you hear too much surface noise, then it's too much surface noise. However, I wouldn't count on the record store refunding your money for a used LP.

I'll put up with more noise if the record is a hard one to find or if the underlying sound is especially good but Tvad is right, everyone's tolerance differs. Digital sensitized many to this more I think. The longer you play vinyl, the less a little noise seems to bother.

When it interferes with your listening pleasure.

I'm surmising that styli/cartridges are pretty tough versus most run-of-the-mill record surface issues from an old brochure on the Linn LP-12 I remember reading ages and ages ago which said something to the effect of "even your battle scarred old discs will take on a new life...", but is there a point at which most of you reject the idea of playing a record out of fear of damaging equipment? How bad does a scratch have to be from this standpoint to relegate the LP to the rubbish bin?

I agree with Tvad, that you probably won't be getting a refund on a used record. I am sure the record store's response will be, "Hey, why didn't you inspect it before you bought it?".

(Even getting a refund on a brand new sealed record is no sure thing anymore. I've had more than one record store balk at refunding me money on obviously damaged vinyl.)

Good Luck!