I want to be able to choose the right branching strategy for most thinkable situations and organizations. So I'm looking for a extensive list of positive and negative effects of extending the use of code repository branches in a development organization.
Please only post one pro or one con in each post, so that the voting system can help rank the feedback somewhat.
Pro: Developers can work more freely in tighter iterations without stepping on eachother's feet.
Pro: if you have many branches you'll be pushed to adopt a modern DVCS (my experience is with Mercurial but I hear git or Bazaar are also good) rather than stay with a traditional centralized system (like, say, svn).
Con (and it can be a big one): Merging back at a point in the future. The longer the duration and the greater the deviation of code base, the harder your life will be. My advice: think very carefully about branching and ensure you only do it when necessary and consider the effort involved in merging at a later date should it be required.
Pro: By keeping latest deployed version in trunk, small fixes can be rolled out quickly without extensive testing of the latest development version.
Pro: Each update is independant from the others, so work can be parallelized.
Pro: Branches can be used to facilitate 'what-if' scenario's in trying out new code. At the end a decision can be made to merge the new feature or to abandon it.
Con: Having too many branches in the air at the same time and you start forgetting where things where commited, where changes have been made etc.
Con: someone has to manage the branch(es) and keep on top of things. In most teams this falls by the way-side.
Pro: Greater flexibility in diverging code for the purpose of simultaneously developing on or supporting multiple streams of work.