Per Article 90.1(B)...to paraphrase..following the NEC will result in a safe installation, but not necessarily adequate.
I'm all for leaving spaces in new installations. I just did a 200-amp upgrade that I thought was around 25 circuits. I installed a 40-circuit panel rather than a 30-circuit. As it turned out, with splitting up some circuits and adding some I ended up around 30 circuits.
In the "to each their own" category, I rarely research circuits to find space (unless I've wired the circuits with my usual over-kill), or use half-sized breakers in a full panel. In my opinion, it's time for a sub-panel or service upgrade.
For every customer who can't or won't go for the expense there are three that appreciate it being done right. Researching and half breakers only delay the problem of an inadequate service, and often these services are 100-amp that should be upgraded to 200-amp.
In this area, many of these 100-amp services have an ancient, worn, cloth-covered service entrance cable barely hanging on the house (thanks to the siders). Researching, mini-breakers and sub-panels aren't my idea of a good solution.
Dave
