I automate as much as I can. Sometimes I'll even "automate" a one-off task, simply because writing steps down in a shell script makes it easier to review what is about to happen and avoid trashing, say, a big chunk of my digital photo album... :-)

Automation doesn't just save time; it also avoids many mistakes caused by fat-fingering things or forgetting step 6 of an 8 stage process.

Also, once you have automated something, you've (at least potentially) created a tool you can share with someone else, which is good for teamwork, delegation and continuity in a work-place.