> all of our more legacy code bases have higher costs for feature delivery Compared to one another, the nominal cost of feature delivery in legacy is higher. T

> all of our more legacy code bases have higher costs for feature delivery Compared to one another, the nominal cost of feature delivery in legacy is higher. This is a correct assertion from the perspective of the person maintaining those systems. But from a business perspective, as long as the operational costs for that component don't exceed it's revenue / value generated, keeping legacy code running is perfectly valid. There's an opportunity cost calculation at it's base: When does the compounded sum of all the time "lost" due to the nature of the code (lacking tests, architectural limits,...) outgrow the cost of decommissioning / replacing the legacy code? As long as the latter costs more then the former, it makes sense to keep the legacy code around. Writing tests comes at a cost as well. The same calculation applies here as well. Is it strategically sound to sink time and money in writing tests if the costs of doing so outstrip the marginal gains on efficient feature delivery over the projected lifespan of a legacy component?