What missing one day actually does
There is a piece of research on how daily behaviours become automatic that speaks directly to the last point, and its limits are worth publishing next to it.
Qur’an and Sunnah
Alqama reported:I asked 'A'isha, the mother of the believers, saying O mother of the believers, how did the Messenger of Allah (ﷺ) act? Did he choose a particular act for a particular day? She said: No. He act was continuous, and who amongst you is capable of doing what the Messenger of Allah (ﷺ) did?
Sahih Muslim 783graded sound, sahihaynfull report
What the research says
Lally P, van Jaarsveld CHM, Potts HWW, Wardle J (2010). How are habits formed: modelling habit formation in the real world. European Journal of Social Psychology, 40, 998 to 1009 doi
96 volunteers took a median of 66 days for a simple daily behaviour to become automatic, with an enormous spread between different people and different behaviours. Missing a single opportunity did not measurably set the process back. The limits are substantial and worth knowing: a small self selected sample, simple health behaviours rather than acts of worship, and everything measured by self report.