How do buddhist monks who are teachers have time for their own practice?

For a while now i have been wondering about how buddhist monks have time for their own practice. When i see buddhist monks like *Ven. Yuttadhammo, Ajahn Brahm and Ven. Bhikkhu Bodhi* who contribute so much to the teaching of the dhamma and have set in motion so many initiatives like making videos, written books, teaching pali language, teaching on retreats etc. i wondered when and how they have time for their own practice? Thank you for your time. Lanka