Choose the right container.

AVOID containers with small, narrow rims, which are going to limit the amount you can plant.

If you want to cut down on watering in the summer, choose the biggest container you can find (provided you are going to be able to move it if you need to), as the more compost you can put in, the longer it will take to dry out if you forget to water occasionally.

Don't be misled by 'frost-proof' terracotta. It may be a better grade that is less likely to crack but it isn't indestructible, as I've often found to my cost. You'd be wise to cover your terracotta containers with bubble wrap in winter or move them into a sheltered spot near the house if frost is predicted.