Currency really is one of those things that comes back to your own comfortable level of risk acceptance (accept in the case of club aircraft where the choice is taken out of your hands). It's a bit like low flying, aerobatics or even just flying ... no matter how experienced you are, there is a risk! The less current you are, the higher the risk that you'll get things wrong. However, I'm also of the opinion that currency can be over emphasised, especially by some clubs (the cynic in me, wonders if a little profiteering goes on in the name of "currency"?). As a aircraft owner the responsibility for keeping current within the legal requirements is placed on your own shoulders. I've never found this a problem and approach the whole thing on how I feel at the time. I have gone months without flying and simply picked a good day, kept the flight simple and felt very comfortable with the whole thing. I have to mention though, that the type of aeroplanes I've owned have all been simple PFA taildraggers with few avionics to worry about and distract attention, which makes staying ahead of the thing easier.
When I was in my twenties I would often go months without flying and have no problems whatsoever checking out (ie, one circuit and off you go) but a couple of years ago it felt a real struggle getting back in the saddle after a one year gap. So age must be one factor IMHO (I'm now 41).
Like others have said, it's not the simple flight that will test you, but rather the unexpected problem that could cause cause you to cock up if less than current. That's why I consider that it comes down to your own assessment of acceptable risk.
SS