I think it's a matter of finding an industry that is conservative or for which the underlying business structures / calculations don't change. Myself, I've been

I think it's a matter of finding an industry that is conservative or for which the underlying business structures / calculations don't change. Myself, I've been working on real estate feasibility analysis software for 12 years now, and the product had existed prior to that for perhaps 10 years; the core calculations have made the journey from Turbo Pascal -> Delphi -> C# .NET. The next iteration of the project is a web-based version, but it'll still (re)use the same core calculations. The target market - real estate developers and investors, mostly - don't necessarily want anything new and exciting; their needs are best served by software that delivers the same calculation results over many years, and that they are used to working with.