Well I takeoff on flaps “T/O” position mainly due to the reduced stall speed (I think i is 7 knots). This, in turn, translates to earlier liftoff, and greater margins in case of engine failure very low down. It accounts for a significant improvement with my Comanche at MTOW on any runway below 800 meters length.
As the Comanche has fowler flaps, you do note the difference in between “increase lift” on T/O position and “increase drag” when extending further.
But as said before, any aircraft needs to be flown according to its POH.
While most MEPs use flaps for a short field technique, it can either lead to wheelbarrowing or lift off before safety speed. Hence the majority of light twins the normal take off is flapless.
I agree with @UdoR and use flaps 25 as per POH in the Warrior, to save wear and tear on tyres and airframe (grass runway). Perhaps PPL hire aircraft use flap 10 on the Warrior because it has a low flap Vfe? The Vfe is the same. Or they don’t train to retract in stages? Retracting flaps 25 in one go at best angle of climb speed will almost certainly produce a stall warner and a sinking feeling.
How serious is the difference in tyre wear is there between a flap less take off and a without flaps take off? Even if it increased roll distance by 200 metres the tyres surely wouldn’t wear out that much quicker. A few heavy breaking landings would wer them much quicker I would have thought.
With my Ralley Club I use flaps almost always for take-off, usually full. It seems to climb pretty much the same way regardless of the setting, and the manual does not make much difference for that either. The reason may be the slats which are open – if you want to close them to reduce drag, you have to level for several seconds and with load they will open again when you lift the nose. So we lift off with flaps on, level in ground effect to get speed to 90-110 km, start climbing and slowly take flaps up.
I cannot tell if using flaps save any money, as it probably adds gas consumption a little, but as tires cost about 300 a piece, it hopefully saves them. Decades ago I read about some (probably German) test about car tires, where they found out that the tire wear increased dramatically (30-50% if I remember right) when the car speed went up just a little like 80→100. So I hope to avoid some wear if the plane gets airborne 10 km/h earlier. But like mentioned, I have no clue if that actually saves money if we count everything…
Anyway, the short field t/o is pretty good with an empty plane on hard surface and short field technique: I can get it off at 80-90 meters. Not too bad? I really like that plane and would not even have money for your planes. This is off topic but when we were watching one of those planes which you are always talking about (the owner earns 7 millions per year) I mentioned to my son: “I would not even want to have such a plane because with it you cannot use common farmer fields like we do when the hay is cut off”. We have different needs and different planes for those needs, and that is good!
As the M20C is mentioned earlier, we have always operated it according to POH, which means take of with flaps 15°. What I did notice during this time is that it is ready to fly rather quickly, will unstick early and be off the ground after a comparatively short ground run in comparison to other planes. Mooney has take off flaps in most if not all their POH’s on all models.
We once did a formation take off with an Encore. We were behind, he before us. We were airborne much earlier than him, but he zoomed away after he was airborne, but the take off run was noticably longer. We use flaps 15 and of course are lighter, the later models use Flaps 10. So there may be a good reason why Mooney does that.
Pilot_DAR wrote:
I have never seen a flight manual refer to a “stage” of flap.
I learned to fly in the US and my instructor, some 25 years ago, used that term.
My experience has been that every plane I’ve flown whose flaps were not manual, have flaps which could be set at any desired angle.
The TB series must be an exception. They have IIRC 10 and 40 degrees.
There is known to be a trivial mod to make it fully variable but it is prob99 illegal 
@hanski I totally agree with your sentiment on the Rallye, very impressive STOL performance and can take all sorts of punishing fields, they have the added advantage of still being reasonably priced to buy and not too heavy on maintenance either.
I just can’t get on with that nose wheel for some reason. I was told.I should treat it more aggressively and to keep my legs and feet loose.
The TB series must be an exception. They have IIRC 10 and 40 degrees.
Diamonds have electric flaps with two positions (besides 0) also.
C152 has 3 flap notches. C150 has continuous flap positions. Flap control is in up or down, and continues when released
Accidentally hit the flap control up and it will go fully up.
Bolkow Junior has continuous flap positions, but flap control has to be held, if released flaps stop.
I can see that low touch-down speed should reduce tyre wear, going from stationary wheel to rotating. I doubt the wear on the take-off roll is significant compared to a long taxi on a hard runway.
I suspect wear is less on grass.
