herbs?

It'll need tidying at some stage but when its flowering isn't the best time. I normally tidy and divide the harder herbs, if they need it, earlier in the year around April.

Let it flower - bees love it although the flowers are also edible. 

Tidy it up when Argyllie suggests - but don't expect it to regrow if you cut back into the woody stems rather than the softer shoots.

It will become progressively more woody as it gets older - I find both layering straggly stems and taking cuttings just as effective as dividing the plant.