Only someone on site can tell you for sure. They need to be in good condition obviously, they need to not have the spike holes (if there) not hogged out and tire up. They need to be proper lengths so you don't end up with a bunch of short pcs. You will need to buy brackets, leader straps, and other accessories so be sure you are prepared and have a source for the correct parts. The new parts will also be much briter and cleaner for quite some time.

I'd jump on those gutters if there is enough to do your house. It doesn't matter if sections are to short or to long, a coppersmith can configure them any way needed. When patina forms they will last centuries so it's not like they've rotted out, the only problem I'd see if they were battered up beyond repair.

copper gutters weigh between a pound to a pound and a half per foot. Scrap copper sells for around $4 a pound so if you can get them around that price it's a good deal in good shape. Don't forget the Hangers and Brackets , you can't attach dissimilar metals that will cause corrosion and destroy any part of the gutter it touches.

I always wanted copper gutters, especially the style which is flat in the back and a decorative front that looks like crown molding. Are they decorative or half round? What was the age of the house they came from?

If the existing copper is sound, reuse can work, but have the carpenter or a gutter specialist inspect it before removal. Check for pinholes, split seams, stretched nail holes, corrosion or dissimilar-metal contact, and whether each section is still straight enough to re-slope. Photograph and label every run, and remove/transport it with wide support so it is not flexed or dragged. Plan for new hangers/straps and compatible copper or brass fasteners, and confirm the fascia/substrate is solid. Test-fit and water-test each run before finishing; salvage often still needs new end caps, outlets, miters, and downspout connectors. A written labor/material estimate compared with new copper will show whether the salvage savings survive the extra handling and repairs.