With the caveat that I charge a bit less, and have only had two clients (but kept them each >1y, and have gotten other client interest I did not have bandwidth

With the caveat that I charge a bit less, and have only had two clients (but kept them each >1y, and have gotten other client interest I did not have bandwidth for): Keep up with the talented people you worked and want to school with. If you are in your 30s, some significant fraction are managers with budgets. At any given time, a few will have a need which is too time-sensitive for the whole hiring cycle (which can take >>$10k and still return a dud). If they remember you as dependable and all-around competent, they would be thrilled to be able to deploy their budget against the problem nearly instantly.