Day one is adrenaline. Day forty is when you find out what your standards actually are.

Novelty does a lot of the work at the beginning and then it stops. On the first day the newness supplies energy, attention and patience for free; by week six nobody is impressed, nothing is interesting, and what is left is whatever you actually require of yourself. That later version is the real one. The early enthusiasm was borrowed.

Decide now what the forty-day version of you will do, and make it small enough to survive a bad mood. One standard you will not drop whatever the week looks like. Write it somewhere you will see it once the novelty has gone.