Regarding houses, an estimate is an estimate. Unfortunately for the builder, though, it is usually treated as a quote. IME the work is never completed on-time,

Regarding houses, an estimate is an estimate. Unfortunately for the builder, though, it is usually treated as a quote. IME the work is never completed on-time, but the estimate (rather than the time) is still the basis for the invoice. It is different with software estimates; I've never given an estimate to a customer, it's always been to a PM or a salesman, who then imagines a quote to give to the customer. In the early days, devs were "given away" by the salesman as part of the hardware deal. As a consequence, dev work was a cost-centre. I'm glad that stopped happening!