I don’t think you want to replace one joystick microswitch at a time if you want to keep them in balance. I’d say do at least two at once, OR replace all of them at the same time. Generally, if one switch is showing its age/large wear, the others are probably not far behind unless that one switch was defective to begin with.
(Weird that the squeak is the microswitch… Usually the problems people have are with dried lubricant on the pivot bearings or pivot space.)
I know it’s tough to have ‘only’ one or two bad switches. You’re still generally better off replacing in pairs or all at once for balance’s sake.
I have a 0.187-tab clone joystick I bought last Christmas that has horrible microswitches in it. They’re far too soft and don’t “fire” well when I use the joystick with fighting games. I’m looking to upgrade those with higher-quality brand name microswitches. Funny thing is that I have another copy of the same joystick with the same off-brand microswitches and they work perfectly fine! Sometimes, it’s just the luck of the draw.
The one advantage that a 0.187-tabbed/non-PCB joystick has over a joystick with microswitches soldered into a PCB (“substrate”-type joystick) is the ease of replacing components. You can easily replace microswitches in those control levers without any soldering iron. The switches are held in place by plastic poles that go through holes in the switch casing. With the 0.187-tab levers, you really can replace micros in pairs fairly quick.
The big disadvantage of the 0.187-tab sticks is that you need to buy a harness converter cable ($3) to use them with the current Mad Catz and Hori joysticks unless you want to reverse-engineer/cobble up your own converter. (Making your own harness cable is a pain-in-the-butt, takes a lot more time, AND costs more money than just buying the same thing pre-made. Rule of thumb: If a part you need is readily available and not outrageously expensive, don’t make it yourself, buy it!) The converter cable itself can be a pain-and-a-half to figure out because it hooks up in a specific pattern for correct signal transmission… it may not hook up in the same pattern for every joystick case depending on the manufacturer’s PCB for that specific model of joystick case. 5-prong/PCB joysticks are a lot easier to install in joystick cases. 5-prong sticks are priced the same as 0.187-tab sticks so it’s generally not to your advantage to buy the 0.187-tab sticks unless you have no alternative or like playing with microswitch mods and swap-outs.