To build or not to build (meaning sell)

Many of us suffer this addiction. We never see the cars as it sits in front of us. We see them as they could be. Looks like the general consensus is to sell it to someone worthy and catch up on the others already under way. I concur, sell it. I face similar questions in my shop. At 60 I think to myself realistically how many more years can I physically do this, at best twenty. Takes me about five years per car. Answer 4 max on property.