Notwithstanding this, like fellow avantgardist Dame Zaha Hadid, he actualised relatively few buildings from his designs. Alsop estimated that only about 10% of his designs have been built. However, this does not worry him because he enjoys designing buildings even when he has no particular commission or competition in mind. "It's like tennis – you have to keep doing it all the time, whether you have a client or not. I believe that absolutely. You can speculate in your sketchbook – you're allowed to think about anything, with or without a client."