Dividing herbs in pots?

[AllInContainers]

Before I learn the hard way ... ... what's the score with splitting herbs in pots which would need dividing in the ground? My sage and lemon balm are fine for this year, but I feel the pots are pretty much maxed out which may cause issues next year. Looks like my pineapple mint might be heading the same way.

If I leave them in the same pot, will they sort themselves out and self-regulate next year's growth, or do I need to tip them out, divide them, and only repot a percentage of the original? If so, any hints and tips on techniques, or is it just lay it on the floor and put a spade/shovel through it?

[Fleurisa]

Sage is shrubby so won't split like that, cuttings is the usual way to propagate them. I think a spade pushed through the lemon balm should work

[Ocelot]

Yes, I've divided lemon balm like that - you can be quite tough. Sage won't like it.