Next to the 6 approaches in the last 6 months there is the requirement as stated below:
Every six months you need to perform at least six instrument approaches, holding procedures, and intercepting and tracking courses through the use of navigation systems. Failing that, you have, as was the case with the old regs, another six months to get current before having to take an instrument proficiency check.
This is taken from AOPA's website:
http://www.aopa.org/pilot/features/ii_9802.html
Another nice link:
http://afs600.faa.gov
Last but not least, when it is very long ago since you got yor IR, I would take recurrency training, but legally all you need is a
succesful IPC to get your FAA-Instrument-rating current again.
Happy IR-flying!
grtz from TZ,
Herbs, CFII
If you have more questions PM me.