It's a worn-out response, but I totally agree that there is no set age-limit for the family bed, though I could understand that families may have their own limits for various reasons.
As for us, I have no plans for ds to have his own bed, though we will need to add a bed/mattress for some more room!
I never ever co-slept, nor have my siblings. My mum believes that it's a bad idea to sleep with babies over a couple of months old because they'll come to like it and will never get out. Sadly (I think), my younger sister became sexually active at around age 14 - I don't think my mum realised this, but I bet that she would prefer my sister occasionally jumping into their bed, rather than in the bed of some neighbourhood boy.
Better that your children know you are always there for them at any age - maybe then they will be less likely to seek out other dangerous "comforts"?