Hi aphrodite,
You can replace level 1 with 2, but maybe only when you feel
that you have no more physical problems. If you wish to
keep doing level 1 after that, then by all means do so. After
four years of sfq, I still do level 1 quite often, not that I
feel the need to, but I still enjoy doing them. I usually do
Level 1 in the morning and level 2 in the evening.
Enjoy both.
Gabby
