Yup. There should be dedicated circuits for your fridge, stove/range, etc. already. Having a dedicated microwave circuit will depend on your kitchen design. If there's a dedicated location for your microwave, that circuit should be dedicated. If not (and it's just sitting on a counter, plugged in to the kitchen outlets, then it's probably not.
That seems to be the difference I've found.
My older home has a shared fridge circuit, something I'm planning to have fixed soon.
The kitchen outlets in my home are also connected incorrectly.
Kitchen outlets, given most kitchen appliances are high drain, should be split phase top/bottom. Usually installers utilize 14/3 cable here (or 12/3, if you're running 20A breakers), which have two hot (L1 and L2) plus neutral and ground (the ground isn't counted in the wire labeling, since it should be included in all lines). So if you go from hot (top outlet) to hot (bottom outlet) with a meter, it should show 240v or something close to it. If it shows zero (or close to it), then it's wired wrong. Those outlets should also be GFCI or AFCI protected, usually by a single GFCI outlet (which will be the first in the line) or via the breaker... You can get GFCI/AFCI breakers.
This allows double the current to be handled at the outlet in the kitchen, reducing the probability that you'll blow a fuse/breaker when using a couple of high power appliances (like blenders, etc).
There's a lot of interesting engineering that happens with home electricity writing, and I'm certainly not an authority on the matter. I've learned a lot from technology connections and other electrician YouTubers.
I need to know a lot of this stuff as a hazard of my work. Since I work in IT, I need to be able to calculate power budgets on the fly and figure out if we're overloading a circuit (or if we are likely to), when setting up racks of equipment.
So you can sometimes find me in the server room looking at power supply labels doing math to figure out if we're okay. Let me say, people are not happy when you tell them the 500VA UPS they just bought isn't sufficient to run the hardware they bought to run on it.
Converting volts, amps, watts and VA is kind of a requirement. Pro tip, for most things, VA is roughly equivalent to watts. Enjoy.