I only ferlilize when they are out side. But thats just me. These things just don't seem to be at all picky.

When I used to use a product called Cactus Juice for my succulents, I'd give some to the Sans as well. As I no longer use that stuff (hard to find & not cheap), I give them a bit of whatever I mix up for other plants. Sometimes it's older liquid MiracleGro I'm trying to finish, other times it's 20-20-20. But I only fertilize them maybe twice during Summer, maybe once in Fall if I remember, then not again 'til the next year.

I think I gave them all a little bit of MiracleGro (8-7-6) a few weeks ago, then last wk a bit of Superthrive to say welcome to Spring & active growth.

I use a slow release pearled type fertilizer mixed into the dirt when I replant. Then nothing but water and sun, cover when chance of frost hits your area. I move mine into the screen porch or car port for the winter. They can take cold weather but will yellow permanently with frost so they don't look as nice. In Florida zone 9 you will find you need to re-pot every 3rd year, so then I put in the fertilizer again.

I water while they ae growing, and fertilize after. When they are pushing up new leaves, up to October, they need water and fertilizer to feed the new growth. Mine flowered all winter during their dormant season, then they will start growing like mad in the Spring.

From laziness and also for fear of forgetting to feed things regularly, I mix Osmocote granules (green cap, 14-14-14) into the soil when potting. It seems to work for all my succulents, not just the sans.