e.g. I usually started my day with the thing that had woken me up. Or you must use past perfect only in specific situations.
1 Answer
If I understand you correctly, what you'd like to know is if a sentence such as the following is possible:
When I was younger, I could only watch television if I had finished my homework first.
The past perfect (had finished) is fine here. The entire scenario refers to a repeated, iterative situation in the past, not to a single event.
To summarize, the past perfect serves to locate a situation before some other point or situation in the past, regardless of whether that situation occurred once or was a habitual, iterative past situation.