If your routine depends on inspiration, your future depends on luck.

If the only days you work are the days you feel like working, then your progress is set by something you do not control. That is a fine arrangement when the feeling is frequent and a disaster in any season where it is not, and the seasons are not up to you either. Building on inspiration means building on weather. The structure is only as reliable as the mood underneath it.

Decide what happens on a day with no enthusiasm at all, and make it specific: a time, a place, a smallest acceptable version. Run that plan a few times deliberately while you are uninspired. Once it works without the feeling, the feeling becomes a bonus rather than a requirement.