I have created a few websites so far and I used containers for all the websites that I created. My collegue says, it is easy and good practice to "TURN CONTAINER OFF" and insert all HTMLdirectly. Then there is no necessity to write container.ascx and write CSS for that container etc. Which is the good practice in general? Should the container be turned on or turned off? Which practice is the best in general and why?

Thanks

Not sure what his reasoning would be aside from reducing markup bloat, however that's more of a design issue than an implementation issue. Myself, I use containers fairly frequently, mainly to give me a sensible place to use H2 and H3 elements (as the container titles). Also, for older DNN sites, I found myself spending a LOT of time manually turning the containers on-and-off, if you are going to implement it site wide, maybe just make a 'bare' container with nothing besides the action menu, links, and content pane.