valve spring damage - solid height

yellow rose said
How long did you leave it compressed? One time to stack won't hurt it.

Edit: I always check for coil bind with the retainer on, unless it's a single spring.

I don't remember exactly but I'm almost certain I only compressed it fully, long enough to measure it with a vernier caliper. I think I did it twice to double check. Thanks to all of you guys for the responses.