There is no free time; there is only time taken from something else.

Hours are not created, only reallocated. A free evening is one you took from something else, and when a new commitment appears to fit into a gap, the gap was doing something, even if that something was recovery. Treating openings as costless is how schedules quietly become impossible.

Protect one block a week that is already spoken for by rest or by people you love, and treat it as booked. Not aspirationally, actually. Defending it means saying a real no to something that will sound reasonable.