- If we do it <this way>, will <this requirement> be impossible to implement (without a huge rewrite cost) later? If so then, if <this requirement> is a realistic possibility, consider <this way> is probably a poor choice
- If we do it <this way>, will <this requirement> be harder to implement, but not terribly so? If so, then weigh the cost/probability of doing it and it not being needed vs not doing it and it being needed
- If we do it <this way>, will <this requirement> not be any more cost to add then if we did it now? If so, then don't do it now. Because you're risking unneeded time for no benefit
Admittedly, all three of those are the same "equation", just the three ranges of where the numbers stand. But it's nice to specifically ask the first and third questions... because they can cut short the analysis.
- If we do it <this way>, will <this requirement> be impossible to implement (without a huge rewrite cost) later? If so then, if <this requirement> is a realistic possibility, consider <this way> is probably a poor choice
- If we do it <this way>, will <this requirement> be harder to implement, but not terribly so? If so, then weigh the cost/probability of doing it and it not being needed vs not doing it and it being needed
- If we do it <this way>, will <this requirement> not be any more cost to add then if we did it now? If so, then don't do it now. Because you're risking unneeded time for no benefit
Admittedly, all three of those are the same "equation", just the three ranges of where the numbers stand. But it's nice to specifically ask the first and third questions... because they can cut short the analysis.