CIO Magazine recently detailed the pain companies go through with ERP upgrades (via Jason Klemow's AnalysisZone). When your read the article, mentally replace each occurance of "ERP" with "CMS" and nearly all of it will still hold true. The piece offers four useful strategies for successful upgrades. Our favorite: "flush the custom code." Better yet, isolate it properly in the first place. This might not protect you from the types of major rewrites that continue to plague a middleware space still in transition to Java and .NET, but forewarned is fore-armed. We know plenty of major corporate CM systems stuck on very old versions because the prohibitive cost of migrating all the custom code...
Read the CIO Magazine Article