Coleus were commonly grown as houseplants during the Victoria era (and later), so a very suitable plant for container growing. They are intolerant to cold so must be brought indoors when temps drop to around 45F (do not allow to go below 40F) but can overwinter indoors easily in bright but indirect light.

A mature coleus can be a good sized plant, so they can accommodate a variety of container sizes, generally moving up in size with repotting as the plant grows larger. I wouldn't start out with anything much below a 1G container. And you want a good quality, fast draining potting soil, like 5-1-1. I can't tell you how often to water except to say as often as it needs it :-) There are too many variables involved to be more specific, but generally if the top inch of the container soil is dry, it is time to water.

Thanks for the reply and for the info!
How long do they live for if I may ask (if cared for properly)?

Indefinitely :-) Pinch back frequently to keep plant bushy and dense and to remove flowerheads, which generally serve only to elongate growth and weaken the plant. Coleus are easily grown from pinchings or cuttings rooted in water so even if your momma plant starts to decline, you can have multiple replacement plants.