In the campaign i am working on, the party will have a lot of days where they will only have one encounter, simply because some parts of the world are simply not that dangerous, they will have plenty of 0 encounter days. And then throwing in 3 encounters in one day, in the same "safe" area would be weird. While one random encounter every few days is reasonable.

I am afraid a sorcerer will just start throwing all his most powerfull spells at the encounter. Making the encounter less challenging.
I am using a sorcerer in this example, but can be any class.

I am considering a few options:
1. Don't do anything. Obviously this is a common option, but not the one i prefer. But maybe people can convince me it won't be that much of a problem.
2. Up the CR of the encounter. This is obviously an option, the Sorcerer does his nova-thing and the encounter is still challenging, but i am not sure i like the sorcerer taking the spotlight on every of those encounters where he kills half the encounter and the rest of the party the scraps.
3. Limit the sorcerer. I heared about spells/encounter instead of spells/day, but that is a too big of a change. I thought of the following idea.

The sorcerer might have 3 level 3 spellslots, 5 level 2 and 7 level 1.
If level 1 spells counts as 1, level 2 as 2, and level 3 as 4 points, this adds up to 29 points. I only allow a spellcaster to cast half of this in one encounter, rounded up, so 15 points. Now that i am typing this, it still allows the spellcaster to cast 3 level 3 spells and a level 2 spells before he is almost out of points, which doesn't really help much. Maybe i need a second ruling, where you can only cast half your spells/day rounded up every encounter. So a max of 2 level 3 spells, and 3 level 2 spells.

I am not sure this works, and i feel going down to like a third of the spells is too prohibiting.

How do other groups solve this, or just not consider it a problem?