I just spent an entire toast cycle at 250 degrees, due to the terrible design of the temperature knob:
A sharpie can put a nice black pointer on the business end of that knob in about 10 seconds. Red or black nail polish is another method.
I have several “customized” knobs around my place.
Already done!
I had to ask permission from my wife before I could “fix” it.
Yaay!
I also occasionally use white-out for these kinds of fixes. The stuff dries sorta lumpy, which gives good tactile feedback for stuff used in dim light where feeling the controls is at least as useful as seeing them. Once dried, it doesn’t wash off with ordinary household cleaners unless you scrub it aggressively. So it’s mostly but not entirely permanent.
Happy Doperversary! May the rest of today be spent properly toasted. 
We had ours wired in. They had a ten-year life cycle. After ten years, they obediently gave out their warning chirps, but there was no way to stop the still-functional alarms from making the noise other than to remove them. The brand was still in existence, but (of course) they no longer made alarms with the same fittings, so we had to call out an electrician, which meant waiting a couple of weeks. (#2 went a few days after #1; #3 was still going strong when we replaced it.)
Fortunately, we did not have a fire in that period, but it seems like it would have been easy to give a one-month warning so you could get them replaced in time.
Huh. Cake day.
Who knew?
I’ve done that a lot. Works great.
I also do that on keyboards when the home key nubbins wear off.
In my engineering life building stuff, an audible fault or status indicator is almost always the worst choice, for the reasons you describe. Ambient noise, room shape, etc can also make localizing or noticing the sound a crapshoot. A visual indicator is always better, a simple flag that flips from green to red on low voltage would be trivially cheap and simple. Even an LED that flashes intermittently instead of a chirp would be superior.
My house has three different detectors in a single hallway (CO, gas, smoke). It was literally impossible to discern which unit was chirping.
That reminds me of my toaster. Looks great, works smashingly, but emits a high-pitched beep when the toast is ready. This “feature” was not indicated anywhere on the box, and cannot be disabled. I hate it, hate it, hate it.
The toast makes a decent amount of noise when it pops up, rendering the high-pitched beep unnecessary. The sound of toast popping up doesn’t carry quite as well, though, so only the beep disturbs the people sleeping in the next room.
We have a washer and dryer that came with the house. They both work fine, but the dryer has an obnoxiously loud and long BZZZZZZZZZZZZ that signals the end of the cycle. My wife hates it and asked if I could disable it, and I said sure - with a pair of wire cutters. She has been reluctant to let me cut the wire to the buzzer, but will probably acquiesce soon.
Just the opposite of our coffee maker. When the brew cycle completes, it emits a very faint beep that I can only hear if there’s no other noise in the kitchen (TV, Sonos, etc.). The same sound is emitted when it shuts itself off an hour later.
So, not annoying, but rather worthless.
Yeah, I have four of them in the same space - one each at top and bottom of stairs and a couple along the transverse hallway at the top - one of them going chirp was the reason for making me write that post. I have no idea what the interval is between chirps, but I was lucky enough that the offending detector happened to do its next chirp as I was walking past.
I suppose any kind of mechanical indicator could jam up and fail to indicate, but yeah, even if they made it chirp, then have the LED flash every 20 seconds, for a couple of minutes, that would help - it would of course use a tiny bit more power, but a very brief flash of an LED isn’t much.
Oh, my microwave, when the timer runs down, goes bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… forever until you get there to press the stop button or open the door. It has already stopped cooking, but it continues asking for your most urgent attention for as long as is necessary until you go there and attend to it.
Which is not usually a problem, but occasionally, the microwave will be running on its timer and I the doorbell or phone will ring, or I will nip to the toilet or something, and the damn thing is just bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop… bo-bee-boop…
It is very handy that I’ve got a lot of high frequency hearing loss. Damn near nothing beeps loudly in my world. Many things don’t even beep noticeably.
Actually it’s a total PITA to have that loss. But if there’s one countervailing upside, it’s the reduction in perceived mindless beeping.
So many of you have that to look forward to. Or may already be “enjoying” it.
[CFO] But that costs extra! [/CFO]
Yep, I have that “upgrade” as well. I wasn’t even aware that my Instant Pot apparently makes noises until the kids complained at me that I was just letting it beep annoyingly for too long…
No worries, in a few years we won’t be able to hear that either. 
Geezers FTW!!
Holy cow ! Really ? We firmly declined to get Pull-Ups during the toddler years. What kind of sadist (or masochist probably) would get them for babies?
Speaking of electronics noises, our new Samsung range sings a little five-note jingle three times when an oven comes to temperature. We have a Samsung washer and dryer, too. This sang songs, too, but we turned that off just art we moved in. It’s an interesting feature.
I recently had a low battery beep on a smoke detector. I thought sure I got the “right” one in the hallway twice, only to find it was one in the guest bedroom that I didn’t even know was there. Whoever installed the 10-year detector didn’t remove the older 9V one.