How often should I clean my BMX bike?
A clean bike is a happy bike. No, cleaning every speck.of sort off the frame after each ride isn't necessary.  

However, wiping down the frame, and wiping any extra dirt or crud from the hubs, brakes and chain can only help keep your bike in good shape for as long as possible.  

Make sure to lightly lube the chain once a week or so. And every couple of weeks, take a set of Allen keys and check that none of the bolts on your bike are coming loose. 

Take it in for a tune every 6 months to a year, and you should be good to go. :)