Just had my chimney inspected as a precaution. The chimney hasn't been used in at least a decade and I believe is original in my 1946 house. The company said I needed to have the flue relined with cement and that it'd cost $3,000+. However, to my eye, it looks as good as one might expect for a 75 year old chimney and it seems safe to use for the occasional fire (we're in Southern CA and will not use often).

The chimney bricks are all in good shape. From the exterior, bricks and mortar all look good (inspector agreed). The fireplace and smoke chamber bricks also look good. However, the flue liner (which appears to be clay tiles in segments) has small gaps where they meet. It looks as if the mortar there has dried up in places over time. This still looks pretty good to me! What do you all think? Is this in fact dangerous? Does it warrant an expensive repair?

Here's the inspection video!

https://www.youtube.com/watch?v=0vb7CG0UjNs&t=2m15s

(The link starts at 2:15 just as the camera enters the flue)Thanks!