Balancing Performance and Convention

markmcb writes "My development team was recently brainstorming over finding a practical solution to the problem that's haunted anyone who's ever used a framework: convention vs. customization. We specifically use Rails, and like most frameworks, it's great for 95% of our situations, but it's creating big bottlenecks for the other 5%. Our biggest worry isn't necessarily that we don't know how to customize, but rather that we won't have the resources to maintain customized code going forward; it's quite simple to update Rails as it matures versus the alternative. What have your experiences been with this problem? Have you found any best practices to avoid digging custom holes you can't climb out of?"