I think I'm having an existential earbuds-based crisis.

I used to think there were all sorts of important criteria to consider when choosing a pair of earbuds. Things like sound quality, battery life, wireless charging, connectivity, customisable controls etc...

But just recently, something has changed.

Suddenly, all I care about is how well they fit.

That's because most buds I try these days sound pretty good and most have decent battery life. And yet, even after all these years, I constantly come up against earbuds that won't stay in.

Oh, and I'm way too old and uncool to care about how they look.

Then, every now and again - maybe once or twice a year - I unbox something that's so well designed, it gets five stars from the moment I power it on.

In fact, the Sony WF-C510 earbuds had me the moment I put them in - before I even started listening.

At first I thought there'd been a mistake. The case was so small and light I wondered if maybe they'd forgotten to put the earbuds in but no, they're just that small. Sony claims to have been collating data about ear shape since introducing its first in-ear headphones in 1982. Now, I know all ears are different but you have to admit, 42 years-worth of data has to count for something and in my case, it was a perfect fit.

Not only is it a snug and secure fit, because the WF-C510 buds are so small and light, it's a super-comfy fit as well. This means you can wear them for hours and hours without any discomfort.

Of course, being so small, I naturally assumed the battery life would be average at best. I couldn't have assumed more incorrectly. Sony claims up to eleven hours continuous use on full charge with another eleven hours in the case. When I first read that, I thought it must have been a typo. If memory serves, I've never tried any other buds capable of reaching double figures when it comes to continuous playback. Eleven is literally off the charts.

So is it true?

Here's the thing... I don't know yet. You can do a lot with the Sony Headphones app; change and customise EQs, analyse your ear shape, assign different controls to each button - and importantly, track your activity. So I know for a fact I've been using the WF-C510 buds for eight days now, totalling 14 hours and 2 minutes.

On a single charge.

The app also shows both buds are still at 100% (and I've been using them for over an hour already today) while the case is now down to, wait for it, 50%.

So, by my calculations, I'm going to blow through that 22 hour combined total easily.

Which definitely softens the blow of my one disappointment with the WF-C510 - no wireless charging. The case is USB-C only. Even I have to concede if I'm only charging it every fortnight or so, who cares?

Oh, did I mention the price? RRP: NZ$149.95 - right down the bottom end of the scale for a pair of premium earbuds.

So you would assume there's no Active Noise Cancelling here. Which is true. Well... sort of. Because these buds fit so well, the Passive Noise Cancellation is actually better than the ANC I've experienced on many other (much more expensive) earbuds. Which is why instead of ANC, Sony has gone with AMS instead - Ambient Sound Mode.

So rather than turning ANC on to block traffic and other noise, you activate AMS when you want to hear the outside world.

Admittedly, this means there is no Adaptive Sound Control, automatically changing the level of ANC to suit your environment but I'm an all-or-nothing guy when it comes to noise cancelling so that's a compromise I can definitely live with.

You still get options for 360 Reality spatial audio and DSEE to help reconstruct the fidelity of compressed files.

This all adds up to a very satisfying listening experience indeed.

Six60's hit "Don't Give It Up" begins with exposed vocals over a simple, booming bass riff and somehow, it does indeed boom on these minuscule buds.

"South of the Border" by Ed Sheeran and Camila Cabello is another fine example of the WF-C510 providing crystal-clear vocals over a precise-yet-powerful bass and rhythm section.

Neil Young and Crazy Horse separate the guitars left and right on "Down By the River" and yet again, the small size of these buds defies physics by creating plenty of space while also, somehow, making Young's voice sound... quite nice.

Because there isn't much surface area to the WF-C510 form-factor, it's a relief they're controlled by physical buttons on each bud - capacitive touch controls would mean accidental plays and pauses every time you put them in or took them out. I was also pleased to discover I could turn AMS on and off with a single press on one bud, while playing and pausing on the other. The only control quirk is volume - rather than a long press of either bud it relies on multiple presses (ie; more than three). This takes a bit to get used to - but at least volume controls are there. That's not always the case.

I can't finish up without mentioning the range, which is not something I always pay much attention to but in this case I thought it was worth pointing out I can leave my phone on my bedside table and still get crystal-clear reception while making a coffee two rooms away on the other side of the house. Pretty impressive.

So the WF-510 sound great, have fantastic passive noise cancellation, unprecedented battery life and above all else, they fit beautifully.

And yes, another advantage of being so small is (although I don't care) they look fabulous - hardly even noticeable from some angles. Available in blue, yellow, white and black, the smallest things I've reviewed this year may just be the best.

Click here for more information on the Sony WF-510.