I have 20a circuits in my kitchen. The GFCI's are 20a, but all the standard receps are 15a. The breakers are 20a and the wire is 12 gauge throughout. Is there any reason to upgrade to actual 20a receps? I could easily swap them out, I just don't know if there's actually a benefit. The breaker in the box does trip sometimes if say a Microwave and Air Fryer are on simultaneously. Does that have anything to do with the actual receptacle or is that just too much for a 20a circuit regardless of 15a or 20a receps? Thanks!
The breaker trips will not be affected, in any way, by changing the receptacles.
15A receptacles are 100% code compliant on a 20A circuit, as long as there are at least 2 - and a duplex counts as 2.
The only reason to change the receptacles is you have actual 20A appliances to plug in. I have used some UPS (battery backup) and some big copiers that have 20A plugs. But all normal kitchen appliances (toaster, microwave oven, food processor, etc.) that I have seen are designed with a 15A plug, which will work on a 15A receptacle or a 20A receptacle.
The single most important thing is GFCI protection for the kitchen receptacles. That can happen either: at the breaker, a dead front near the breaker, the first receptacle in the string, or every receptacle. Don't use the LOAD terminals unless you know what you are doing; the LINE terminals can take 2 wires per screw.
If you don't have any 20A plugs, it's not going to help operationally.
The default 15A socket is a "builder grade" cheapie (60 cents), and most 20A sockets are the better $3.00 "spec grade" types. But you can buy spec grade either way.
There are a large number of complications that can arise when changing receptacles. Thus, leaving well enough alone is sometimes wise.
Science has recently revealed that torque settings really matter on small receptacle screws. So switching from properly torqued 15A outlets to haphazardly torqued 20A is a downgrade.
The breaker in the box does trip sometimes if say a Microwave and Air Fryer are on simultaneously. Does that have anything to do with the actual receptacle or is that just too much for a 20a circuit regardless of 15a or 20a receps?
Read the nameplates. The microwave will state that it draws between 10 and 15 amps depending on model. The air fryer will state 1500 watts (12.5 amps).
How do you power both from a 20A circuit? You don't run them at the same time.
Most appliances are limited to 1500 watts because of UL rules (and an NEC limit to 80% of plug rating, so ~12A on a 15A plug).
Any heating appliance generally runs at the maximum.
15A sockets are only allowed on 15A and 20A circuits.
20A sockets are only allowed on 20A circuits.
Ergo it is impossible to run 2 plug-in heating appliances (12.5A + 12.5A) on the same circuit at the same time.
Modern kitchens must have 2 or more circuits that supply only kitchen area receptacles. Use the other one, or feel free to have more installed.
I swapped all mine in the kitchen for 20 amp receptacles, but not because I would ever need the 20A socket. The original receptacles in the kitchen, and really in most of the house, had lost their spring on the electrical contacts inside. Sometimes we'd have to wiggle the plug in a socket to get it to work, and often a cord would simply fall out of a socket under the strain of its own weight.
Commercial or pro grade receptacles are molded of stronger resin and have better terminals inside. I've replaced the high-use receptacles in my house with these (ie all of those in the kitchen, garage, and the ones in the hallway where the vacuum cleaner is routinely plugged in).
At the time I must have thought that commercial/pro grade was only available with the 20A socket configuration but in a search now I see that's not true (at least in the Leviton brand). I guess it's possible that a given retailer chooses to stock commercial/pro only in the 20A style.