ON ANY PROJECT THAT IS IN PRODUCTION (i.e., it has customers that are using it), there will come a time when a change must be made; either a bug needs fixing, or a new feature must be added. At that point there are two possible choices: you can take the time needed to “do it right,” or you can take one or more “shortcuts” and try to get the change out the door sooner.
Generally, the business people (sales/marketing and customers) will want the change made as quickly as possible, while the developers and testers will be more interested in taking the time to properly design, implement, and test the change before delivering it to the customers.
As the project’s architect, you’ll have to decide which makes more sense and then convince the decision makers to take your advice; and, as with most architectural issues, there is a tradeoff involved. If you believe the system is reasonably stable, then it may make sense to go the “quick and dirty” route and get the change into production quickly. That’s fine, but you need to know that in doing so your project is incurring some “technical debt” that must be repaid later. Repayment, in this case, means going back and making the change in the way you would have if you’d had the time and resources to do it right the first time.
So why the concern over making changes properly now versus later? It’s because there’s a hidden cost to making these quick and dirty fixes. For financial debts the hidden cost is called “interest,” and most anyone with a credit card knows how expensive just paying the interest on a debt can be. For technical debt, interest takes the form of instability in the system, and increased maintenance costs due to the hacked-in changes and lack of proper design, documentation, and/or tests. And, like financial interest, regular payments must be made until the original debt is repaid.
Now that you understand a bit more about the true cost of technical debt, you might decide the price is too high and you can’t afford the cost. But when it’s a choice between having the developers get the fix out as quickly as possible or taking a severe financial hit, it generally makes sense to get the fix out quickly. So, take the hit and get the change into production ASAP, but don’t stop there.
Once the fix is in production, have the developers go back and fix it properly so that it can be included in the next scheduled release. This is the equivalent of charging something on your credit card and then paying off the balance at the end of the month so you don’t get charged interest. This way you can provide the fast changes the business needs, while keeping your project out of debtor’s prison.
97 Things Every Software Architect Should Know
By: Richard Monson-Haefel