For Body, breath and mind (upadhees) regular sadhana is needed to control the Rajas and come out of Thamas and get into Sattva. So to be done daily. (Kriya yoga)
For intellect - knowledge is very very essential. So daily one should be in touch with the knowledge (Gnana Yoga)
For memory - to clear the chiththa one has to practice Seva. Selfless service. (karma yoga)
For Ego - One to be in satsang and surrender (Bhakti yoga)
7 levels - Body, breath, mind, intellect, memory, ego and self
4 yogas - Kriya yoga, Gnana yoga, Karma yoga and Bhakti yoga
Bhagavad gita talks about three gunas and how to manage them.
