I once worked for a very successful software company with a customer base that included government (IT installations), academic (college courses lab work, hardware research), financial (banks), and industry (computer hardware manufacturers).

We built a platform, and had a consulting wing that built custom "apps" on top of it.

We did Waterfall and CMMI. Waterfall was most intense for the consulting projects. I remember being assigned to build feature 3.2.2.1 in the spec.