All year round.
Look for unblemished, firm limes that feel heavy for their size as they will be the juiciest. If you intend to use the zest, buy them in-waxed (shops should state this clearly). If you can't find un-waxed limes, scrub the limes thoroughly before zesting.
To extract the maximum amount of juice, make sure the limes are at room temperature, and firmly roll them back and forth under your palm a couple of times - that helps to break down some of the flesh's fibres. Alternatively, microwave them for around 30 seconds, depending on the size of the lime - warming them up also helps them give up more juice.
In a perforated bag in the fridge (for a couple of weeks); in a fruit bowl (for around a week). Once cut, wrap in cling-film and keep in the fridge for up to four days.
Use to make Key lime pie; salsas and curries; marinades for raw fish; add a wedge to a classic gin and tonic or use to make cocktails such as the margarita, caipirinha or mojito.
All the best Jan