When do UC claims close?

How long do UC claims stay open for claimants who have to do no work related activities due to working enough hours per week but are only on living wage? Claimant in question is a single man with no dependents and lives at home still so has no housing costs.

Six months.  If the claimant is not entitled to UC because of the amount of his earnings (and is otherwise eligible in principle for it) and then his earnings cease or reduce within six months he can get UC without having to go through the new claim process all over again - assuming he is in a “live service” gateway area