When I was doing gymnastics, drills every practice. Into the pit most days (running on spring floor) but not always. More days than we didn't. If we had dance maybe we'd skip vault. On hard runway onto hard mats? Pretty infrequently. We did bars more for sure. But pretty much every girl I did L8 with had a tsuk in the first year, and we had several state and regional bar champions. My coach was very good at teaching the skills necessarily. I came to her in L7 unable to do a tap swing and had free hip handstand giants in a few months.
Most girls need more bars than anything in my opinion. We used to go to bars 2 times a practice when my coach decided we weren't where we needed to be. I'm not saying skip the other events, but I allocate more time to bars. Beam is mostly confidence management with some technique (hand placement, punching, alignment), but for the most part we're teaching those skills on the floor. At the lower levels I allocate the least time to beam, and it doesn't seem to hurt much. Vaulting, not every day, because I integrate drills into the floor rotation.
Vault is a lot of pounding. I personally don't think that "most" optionals (just following a standard track) need to do vault every day. The best way to teach them the L8 vaults is to start very early. Kids by about L6 skill level should be flipping off wedge mat/double board into pit or soft mat. If the front handspring is strong, working the 1/4 on action, and doing yurchenko board drills. They need to do many many yurchenko board drills before they're ready to do a full yurchenko. They don't need to practice it every day. I didn't even work out every day, and competed a pike tsuk in my first level 8 meets.