Most of the shower drain problems I see come from the shower pan not being bedded properly and the floor flexing when stepped on.
This coupled with drain pipes that are well secured usually running through a joist unable to flex with the floor either loosens the connection of the pipe to the shower drain or the drain to the shower connection.
I have found this drain made by Davke to be an enormous help in getting the drain well secured to the shower pan and because it connects with a no hub connector allows enough flex to last. Davke 3000 Shower Drain
Sioux Chief makes a similar product called the Jack Rabbit but it doesn't connect with a no-hub. Sioux Chief Jack Rabbit Shower Drain
The jacking screws allow the drain to be tightened where it is usually very difficult due to clearances with the flooring.