The frequency is really up to what you find rewarding or interesting. Some people like to make an observation each day, others might make two or three in total for a case like this - up to you.
You can use the Observation Field “Similar observation set” to link repeated observations of the same individual(s): https://forum.inaturalist.org/t/using-the-field-similar-observation-set-for-linking-observations-of-lepidoptera-when-raising-on/1018