Well Wabe the comparison to lock your house is not really correct. If compared to a house it would be more like: You bought the house and got your keys, Now you decide to buy a new shower. The company comes and install it but when you try to take a shower the next morning nothing happens. Looking more closely at the shower you see a small hole surrounded by the text 'In order to activate the shower you will need a key and it should arrive in a couple of work days'. Or After living in your house a while you realise that you don't like the placement of the house. You would really had prefered if it was placed closer to the garage so you decide to hire a big crane in order to move your hose. Everything went smooth untill the point where you try to enter your house. Now, just because you moved your house a little your keys no longer works on your door......and worse is, the company that sold you the house was bought by Abdulla Oil, witch the US goverment suspected to also creat weapons of mass destructions, so they sent a tactical nuke (a weapon of not so massive destruction) just in case. So sorry, you will never be abla to move into that house again... Well, jokes aside. Zbrush and XFrog works the same way. When I bought Zbrush and found out about the license system I returned the product (I even made some money on the difference in exchangerates between the buy and the return). As Xfrog was a lot cheaper I decided to keep it anyway. The point is that I would never buy anything expensive if I don't get a liftime key with it.