Can I get my slots back if I delete the giveaways?

deleted GA's eat up slots
support can give more slots with a ticket though.... although it looks like their slots are potentially eaten up by lvl 10 required whitelist only giveaways with no winners(I forget if no winner GA's eat slots or not)

A new account start with 3 GA slots.
If you delete 1 GA, you lose 1 GA slot.
You get 1 GA slot for every 3 GAs that are marked as recieved from your winners.

That hidden statement reminded me as something Icaio could have said (or the kind of humour) and made me smile.

Damn that's weird

I would have thought restricting to just L10 would have been enough, but obviously not!

Exactly.
Emphasis on "deleting ongoing giveaways", that will indeed waste the slot too, something some people may find counter-intuitive. Same for giveaways that haven't even started (if created and set to start in the future). So, double-check before you create, and double-think before you delete 👀 Extra slots can indeed be granted, but that will typically be a one-time thing, for users who ended up stuck at 0 slot.

Also obviously, for multi-copy giveaways, multiply by the number of copies.

Edit: one particular case there, if your giveaway ends with no winner, you get the associated slot(s) back too. But you lose them if you delete it.