When the sprint is being planned, the team commits the sprint items as per the available capacity. To target the optimum execution, the team should ideally commit between 80% - 90% of the team’s total capacity, anything beyond that percentage will hinder the team’s performance. Bugs, refactoring, and research requires consistent attention in order to escape building-up technical debt.
Though the teams already have items to work on from the product owner, some of the teams set aside 25% of the capacity for this job. We also have a good practice which the teams can follow, 15-10-5 allocation of the scrum team’s capacity, which means, 15% of a team’s capacity to technical debt, 10% of a team’s capacity to defects, and 5% of a team’s capacity to exploratory work.If the team is able to follow these allocations, it will fulfill both the code quality and upkeep necessities of most software applications.
It is a good practice if followed sprint by sprint, but if for some reason the team is not able to do it in a particular sprint due to high priority delivery, it’s fine.