Depends on where you live. You'd clean it when it gets dirty. I'd check it once a year. You should use a filter recharge kit sold by K&N.

See instructions here: K&N Air Filter Cleaning Instructions

I guess it says 50k cleaning period... Seems a bit long in my opinion.

 

I have been using K&N filters since 2001 in all my cars and I never had a issue. I presently also have one in my toyota which has been installed for the last 72,000 and I only cleaned it once. I inspect the filter on every other oil change and it looks good. No dirt on the inside of the intake. My only recommendations is to make sure its not over oiled and don't use pressure to wash them. As far as jaguars go, I had them installed in my 2010 XFSC with no issues and now my 2013 XFR without any issues. Like I said, Just make sure its not over oiled and you shouldn't have a problem. From my experience, they don't need much attention unless you live and a really dirty/dusty climate. Some members have had problems but maybe I'm one of the lucky ones. Lastly, Check and make sure the production numbers are within one of each other. I think its like paint, the closer they're made together, the last chance of air flow problems although I don't know how true that is.

 

I wouldn't say I live in a dusty place but the regular OE filter gets quite filthy fairly fast. If a K&N didn't then it would have to be letting the muck through.

 

Just cleaned the K&Ns myself about 3 weeks ago. I estimate about 9K miles on them in about 9 months. Since I'm working in the desert, I had planned on pulling them at the 6 month mark for a visual assessment, but just never got to it.

This was the condition when I opened the airbox:




This is what the lower portion of the airbox looked liked:


The upper portion shows how well the filter is working:


Cleaned and dried overnight:


Oiled and ready for re-installation:


Since then, I've pulled the mass airflow sensors and cleaned them to make sure there wasn't any of the filter oil was coating the wires. No problems to report that I can trace back to the filters.

 

thanks to this thread I just ordered a set of filters. cant wait to get them next week!