How often do you get your geometry checked?

Had the 355 a year now - how often fo people generally get a full 4 wheel geometry check done on their F cars?

On my previous car (993), it was really important to get it done once a year to maintain the 'Weissach Effect' of the suspension, any small devations from spec made the car handling unpredictable.

Not sure if it is a similar principle on F cars and in particular 355's?