Ideally, bulbs need around 3 months after flowering to build up their energy reserves for the following year. it is therefore impractical to leave them in tubs when you need to get your marigolds in them.
I would leave them in situ for as long as you can and keep them well watered and a liquid feed once a week.
When you're ready to plant your summer stuff (usually end may ish), remove the bulbs with the leaves on and either let them dry out or plant them in a shady corner of the garden, remembering where they are. They can be lifted and stored when the leaves have all shrivelled and gone brown.