As a rule of thumb the best way to keep your drains clear is to be careful of what you pour in it, however to keep it clear here is a cheap trick.
- Pour hot water in your sink
- throw a handful of baking soda in your sink and follow it with hot water
- pour 1 cup of vinegar let it sit for 30 minutes and then follow with hot water.
This method may be dragging and will cost a little bit of your time but this will greatly help you in maintaining the health of your drain. As they say, big things comes from small beginnings. a little bit of effort weekly may save you a lot for the future.