I've been using a stabilizer/cleaner in everything I have that burns gas for the last thirty years. I don't have carb trouble with ANYTHING and I've never had to have injection service on any vehicle, and I've had two that were among the most needy of special care in the world - a Honda Odyssey with Variable Cylinder Management (VCM) that is known to cause oil fouling in the 'off' cylinders and resulting in sometimes major repairs including engine replacement. The other one I still have, and I love it - a 2017 KIA Sportage SX 2.0L Turbo. This is a first generation DI engine and like all the others, it carbons-up the intake valves because the fuel in the intake stream doesn't pass over them. This continues until suddenly you realize its using oil and running rough because the rings are now carboned-up and stuck. Many makers have been hit with this including Audi, and KIA loves to copy them. Now both of these vehicles have high chances of causing big trouble but the Honda didn't, and I traded it at 90K because we didn't need a van anymore, and it was coming up on some major maintenance work. I had always used the fuel treatment and Mobil1, plus after 55K, I went to Mobil1 Hi-Mileage. The last change I used Mobil1 Hi-Mileage/Extended Performance (20,000 miles) It never used any oil and it had its original plugs and running smooth. Naturally I had no intention of running any oil for 20,000 miles, but that tells me they are confident in the oil maintaining viscosity and the additive package being effective for that long, so for my 12 month oil change at probably 4000 miles, I would have total confidence in that oil. For the KIA, I had been using synthetic since about 10K miles, and on the last change I went with the Mobil1 H.M./Ex. Perf in that too. I could tell the difference right away in engine sound, quietness and power - I think the turbine is spinning a little more free. Anyway, I like this Sportage so much that I'm willing to spend on it to maintain performance and appearance, and since the engine is running so well, it gives me confidence in spending money on it for the long term. On this one. I think the combination of the fuel treatment and the special oil has been sufficient to keep the carbon under control. If more help is needed, there are spray treatments now for the DI engines that you use into the throttle body that will clean them up.
In my view, especially if you use E10/15, you must use a stabilizer for that fuel and you will also benefit from a cleaner fuel system and everything that goes with that. I use Startron mostly but will use Sta-Bil 360 from time to time.
For the outdoor power equipment, I don't do a damn thing on the last use of a mower in the late fall but put it in the shed and lock the door. Next spring I take it out and start it right up. I put the stabilizer in the gas can when I get the gas (I always use Premium) so its always in the mower gas. I use synthetic oil in them too, Castrol Edge Hi-Mi 10W-30. My two 21" mowers are 21 years old and 17 years old.