I do sedum in mine and for a little extra color in the summer I put a cutting of Coleus.
You are right they do not get enough water. Especially if it is terra-cotta. I do not have time to water my summer pots every day so I always put a pamper in the pot to hold moisture. I buy the cheapo 2.99 for 24 at Big lots and all my summer pots are lined with a diaper.
This pot stays out all winter the coleus die but succulent survive all winter. But these pots will even kill sucs because they do not get enough moisture.
-Diaper soaked
-Open so you can see the moisture crystals.
-Spread your soil on top of the moisture crystal
-outside plastic part of diaper against the inside of the pot to help with moisture and the soil inside the pot not drying out so fast.