KTLO/BAU

KTLO (Keep The Lights On) and BAU (Business As Usual) is the operational tax on everything you’ve already shipped. Patching, monitoring, incident response, dependency upgrades, regulatory compliance, on-call rotations — the work required to keep existing systems running. The more you ship without investing in sustainability, the higher the tax climbs.

A common heuristic from flow-based measurement frameworks puts healthy KTLO/BAU at 15-25% of engineering capacity. Below 15%, you’re ignoring maintenance that will compound into incidents. Above 30%, your systems are telling you something: either technical debt has accumulated past the tipping point, or the architecture can’t support the product’s current scale. If KTLO is growing quarter over quarter and nobody’s naming it, you have a structural problem wearing an operational disguise.

The percentage isn’t the danger — invisibility is. Teams that don’t track the split between new value work and maintenance work can’t have honest conversations about capacity. They promise feature timelines based on 100% of the team while 35% of the effort is keeping existing commitments alive. Flow metrics make this visible: when your flow distribution shows maintenance eating a growing share, your technical investment strategy needs attention.

The fix: tag KTLO work explicitly in your backlog. Give it a line in quarterly planning. Treat sustained growth in that line as a signal to invest in the underlying systems, not to hire more people to absorb the load. KTLO you can see is a budgeting problem. KTLO you can’t see is a credibility problem.

Resources

• Technical Investment — frameworks for managing the debt that drives KTLO growth
• Flow — flow distribution metrics that make KTLO visible as a percentage of total work
• Product Non-Negotiables — the “Continuous Evolution” pillar challenges the “build once and KTLO” mindset