ok so whats with this clicking grinding noise?

its been happening a lot lately, like gears are skipping and when it does the print goes out of alignment and gets runined, 

i cant print anything thats large because i need to watch for this clicking and restart the print when it happens, it happened on occasion ever since the first print but now it seems to happen more often than not.

how often do you level your bed?

Check this link: http://support.zortrax.com/hc/en-us/articles/201315441-Eliminating-Layers-Displacement

thanks for the help, im attempting to fix it as we speak, ill let you know how that goes....i dont level my bed often at all, how often would you suggest i do it?