A Switch, a Switch, my Kingdom for a Switch

High-end Panasonic NB-G110P Quartz Element Toaster Oven: it is well designed for a toaster oven in that the pushbutton power switch is low voltage, indirectly activating a solid state relay that energizes the heating elements. But it occasionally wouldn't energize the heating elements unless you tapped the power switch lightly.

2020-07 Update: The second switch I installed was starting to exhibit the same symptom as the factory SW15 switch, so the first thing I recommend now is: unplug the toaster oven, pry off the grey plastic on-off button to expose the head of SW15 and apply some electrical contact cleaner (CorrosionX or MG Chemicals Super Contact Cleaner or something similar) or, less ideally, 91% or better isopropyl alcohol to SW15, work the switch a bit by turning it on and off a lot (still unplugged) and see if that doesn't fix the problem.
(If contact cleaner on SW15 doesn't work go to the steps below.)

It was an easy disassembly, the circuit board is cleanly laid out, and Panasonic makes parts available (hurray for them). The low quality electro-mechanical pushbutton power switch (SW15) is the one thing wrong, yet is only available by ordering an entire circuit board for about the price of a whole new toaster oven. (I think the part no. for the whole board is Panasonic ABR10A175 "Panasonic Pc Board".)

In this instance the switch was disassembled, cleaned and adjusted and reassembled, but not without tiny springs and other internal switch parts flying around and several hours of fussing and cussing with surgical tweezers: not for the faint of heart; soldering in a new switch would've taken a fraction of the time. It's working again, but it feels like a Pyrrhic victory. Despite being well designed this toaster oven (like many other things) turned out to be only as good as its weakest link, which in this case turned out to be its low quality pushbutton power switch.

2020-01 UPDATE: After a while, the switch failed again and I decided to replace it.

The SW15 switch on the Panasonic NB-G110P toaster oven circuit board measures about 6.13mm square at the base (suspiciously close to 1/4” square.) It isn't a perfect fit, but a fairly common 7x7mm 6-pin DPDT (dual-pole-dual-throw) switch will work as an acceptable substitute.

Search on Amazon, eBay, or AliExpress for something like:
"7x7mm DPDT 6 Pin switch"
and you'll see switches that look like the one above pop up. (Typically with a blue switch head instead of a white head.)
(Many low-cost low-quantity sellers on AliExpress if you're willing to wait for shipping from China.)
IMPORTANT: Make sure you purchase an on/off or "locking" version, NOT a momentary version.

NOTE TO Panasonic (and other manufacturers):
1) have component-level parts available (or provide information on and access to component providers)
2) Use a durable, high quality power switch (after all, that's the switch that's going to be used the most) OR design future devices so the switch is easily serviceable (or even unnecessary.)