As the others have said, clay when it needs it. When the paint feels rough, or you can see stuck on contaminants that don't wash off, then it's time to clay. As a guide you could say twice a year, but if you park regularly near a factory or railway line for example you could end having to do it a lot more often then that.
 
right nice one....i am thinkin of buying some sealant... but as you say seal before you wax.... do you seal before dj lime light prime too?
or do you seal the dodo juice too?
 
right nice one....i am thinkin of buying some sealant... but as you say seal before you wax.... do you seal before dj lime light prime too?
or do you seal the dodo juice too?

Wash -> Clay -> Polish/Cleanse -> Sealant -> Wax

The sealant would need to go after Lime Prime Lite (otherwise LPL will remove it) and before wax. Sealants like to bond to bare, clean paint though and LPL leaves behind glazing oils that help give the finish a nice wet look, and is designed really to work with waxes.
So my advice would be either to leave out the sealant and do LPL and 2 x wax, or leave out the LPL and put the sealant on to bare paint after polishing/prep.
 
just a bit of advice if you would like to find out if the paint needs claying place your hand in side a plastic food bag and rub your finger down the paintwork slowly if the paint feels smooth it dont need clay bar.