Did you really mean only 10 external libraries? If you'd said 100 I could understand - I hit a version conflict issue in a recent project on adding what was probably package #60 or so, but solved it easily enough after a bit of googling. And we knew we were using a lot of quite old packages (including .NET 2.1 EF, because of a rare breaking change they introduced with 3.0 that we didn't have a good solution for).