Clogged drains can be easy to clear if the drain pipes are designed properly. If you need to make a 90 degree bend, don't just do it with a standard elbow. It maybe too hard to get a snake down past this hard bend. Instead, use either a gentle bend elbow. The bend is larger to make it plumbing snake friendly.

Another option is to use two 45 degree elbows with a short section of pipe in between. The further apart the two elbows, the easier for the snake to get through.

To help with clogs in the future, when installing the drains, use a Y fitting and a 45 degree elbow. The Y fitting has the first part of the turn and the 45 degree elbow completes the turn. On the straight section of the Y, insert the clean-out fitting. Now you have access to the drain without having to disassemble any connections. Remove the clean out plug and you can gain access to the clogged drain.