In the past, I never really respec'd any of my skills as I hated spending the cash. But, now I find I'm at the shrine quite a bit now rebalancing my characters. I discover the character I stopped playing a year ago now has value, so off to the shrine. Maybe it is also with the releases from ZoS that nerfs the skills, who knows.
What about you?
Whenever I need to for the content that needs different skills/morphs.
To just change morphs costs less than half of what I can make doing daily writs (in just the gold reward, not including the drops) and this is on my character that has every skill point in the game (minus 17 from PVP) and uses almost all of them.
It's really cheap to change morphs.
Changing skills is a bit more expensive, but I only rarely do that.