You're probably right @Trialben. I would be more inclined to go further if I could steralise the gear rather than sanitise (big difference when talking yeast.....). The 'big guys' generally only go up to about gen 7 or 8 (I know of some brands that only allow 4) then recultivate their yeast.
Sanitising leaves behind bacteria spores that will grow with your yeast. If you can steralise that kills spores as well. A pressure cooker is a good way to do it but I've never got round to getting that involved. I figure one or two generations won't build up enough bacteria to cause me too many issues with sanitization only, but that's why I don't go higher.