How important is a power conditioner for CONNECT and CONNECT AMPS?

Aside from performing the same functions as a $10 surge protector, power conditioners are snake oil nonsense.

My ZP100 has been on nothing but surge suppressors since I got it in 2009. No issues.

I have every Sonos device I own plugged into a high quality surge suppressor (one of the two below) except my Play 3s that are piggybacked off a nearby UPS that had a couple spare sockets. We see some nasty thunderstorms here in Arizona as well as some really dirty power from nearby industrial users, even the neighbor's huge air compressor that dims our lights. All leading me to caution.

If you read through the forums you'll see a number of folks asking about repairing blown power supplies in their Sonos devices, a good surge suppressor is cheap insurance and can save you having to replace a Sonos device.

A Tripp Lite 1 is a decent little suppressor, 660 Joule rating and $5000 failure coverage.

The Tripp Lite Isobar 2 outlet is a step up but a bit bulkier, 1410 Joule rating and $10,000 failure coverage. Direct plug-in or extension cord designs available.

the neighbor's huge air compressor that dims our lights.
If that is a frequent event, will just a suppressor be enough protection?

Kumar, That compressor pulls the voltage down over 10 volts when it is started against a partially filled storage tank, less against an empty tank. He doesn't care, he got it surplus and cheap. The voltage drop isn't important to the Sonos as far as I can tell, it doesn't even bother most of my other audio, TV or computer gear aside from the UPS boxes that beep and blink.

We have two workstations provided with UPS power, more to deal with brief outages and to allow our always-on stuff to properly shut-down if the outage goes on too long. Got tired of stuff not rebooting properly due to dirty file systems after power returns.

What I worry far more about than short-term voltage fluctuations are any power spikes that it or the other users in our area are adding to the lines. They are too short to be visible without test gear but far more damaging than a few lost volts. The surge suppressors take care of a lot of the spike energy, that otherwise would have to be dealt with by the internal Sonos circuitry. A lot of my Sonos gear is long out of factory warranty, I do not want to have to pony up for replacement gear even with Sonos' usually generous replacement policies.

Unless someone is seeing their Sonos gear rebooting from power issues a good surge suppressor is going to be plenty for them too.

If it is a 10 volts drop it probably does not matter; the published spec for the play 1 as an example is : Auto-switching 100-240 V, 50-60 Hz AC universal input.

We have 230 volts mains supply and frequent outages that are covered by a back up DG set; but the 30 or so seconds it takes to spool up means rebooting of Sonos in addition to the 30 seconds gap, and the power cycling that happens for all the kit - not just Sonos - every time, every couple of days. Installing the online UPS for the entire home was a no brainer in my case; the battery does not need to be larger than what fits in the same box, so it is a small footprint thing too. But the benefit of clean 24/7 power that never varies from 230 volts is immense and I don't need any surge suppressors anywhere either. Hopefully, insulating all kit including 5 Sonos zones from all fluctuations and power cycling will offset the investment in some way as well. Both music and movie play remain uninterrupted, as do all the lights, which is something one gets used to in a hurry!

So if anyone is thinking about power conditioners, this is the route I recommend. And if such a solution is not needed, neither is a power conditioner.

Digressing, a question on surge suppressors - many types are available, but do they really work? Does anyone have experience of one that sacrificed itself or shut off power during a lightning strike or similar and left the equipment/load completely undamaged?
I have used a few but the visible use was that of connecting multiple loads to one power socket.

Not one of my Sonos pieces are plugged into anything but the wall, aside from my two second gen Play:5s. No issues going all the way back to 2009.

In Germany I had a very nice IsoBar TripLite that got pretty much burned to a crisp by an application of a huge spike when it was accidentially left plugged into an autoformer that was being plugged into the wall. The first two banks had every component crisped and the runs blasted off the circuitboard, bank 3 was badly toasted but the runs survived, bank 4 still had recognizable MOVs even though they were burnt and cracked. The stuff on the first two banks suffered badly, bank 3 and 4 protected the gear plugged into them. A couple photos to TripLite and I had a new bar and a check for the damaged items in a few weeks.

While living in eastern Arizona we took a lightning strike about 100 feet past from our ground mounted utility transformer. I was watching the storm from our front porch, another 75 feet from the transformer, it knocked me down and out for several minutes. If the phone hasn't fried the wife would likely have called 911 by the time I was up to my knees. It pretty much fried everything in the house that wasn't on a surge suppressor. TVs, fridge, stove, dish washer, several electronic controlled lamps, a couple tabletop radios, couple wire-line phones and our microwave. What survived was plugged into good surge suppressors, my stereo system, our computers and my test gear.

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How bad you need one really depends on your situation, if you have good power and no little surprises then you are probably fine without. If you don't have such good power, talk to your utility about getting your power checked, maybe a bit of protection is needed. If you are in lightning country I'd sure get one. Just don't buy junk, make sure you are getting a decent unit that really works.