If you intend to do a 'touch-and-go' at any airfield, then land with whatever flap you are prepared to take off with. This means you dont have that messy retracting the flap on the runway, and you will be much less likely to retract the wheels just after landing later in your flying career. In a Cessna 150 I would suggest 20 degrees. (25 degrees in the PA28) Then take off without touching anything, and retract the flaps in the climb. You will then find that the aircraft is almost perfectly trimmed for the climb. In the Cessna approach at 70mph/60kt reducing to 60mph/50kt at the threshold
MJ <<< runs for cover