Using pressure washers for almost 25 years, neve ever a problem. Best thing ever.
Where do you live? Haha. I think we wash our bikes at least once a week here in Sweden, otherwise it’ll literally be dry mud and other stuff on there forever.
Ill maybe have a 3 week period during summer where it might just be cleaned once…
You mean every 4-6 weeks? 
Sram flat top chains for the win. I put at least 5000km on mine and still well within spec
Bad advice:
Wax lube is the best option in every scenario.
It just doesn’t hold up long enough in wet northern European autumn / winter conditions, doesn’t protect against rust when it’s wet constantly for months on end and it’s clearly not a good option for commuting or any bike that isn’t being babied.
This is straight up madness, unless @Calle is just advocating for swapping out for a freshly waxed chain or something rather than throwing away a chain with such little use.
If you keep your drivetrain clean and use a wax lube ( on the bike you’re clocking up the miles on at least) things last way longer, even in non-ideal conditions.
That life on chainrings is also way off too, they last forever these days and most of us probably swap bikes before wearing them out. You can see this by SRAM moving to non-replaceable chainrings & with embedded PMs and it being a seemingly reasonable choice at this point.
THE WORST ADVICE I EVER RECEIVED…
Yeah, I am not dismissing this advice. I just think it does not apply for many riders who do not race and/or try to eke out every watt from every component. I myself replace chain twice a year: after “good” season (10-12kkm) and then again after “bad” season (6-8kkm).
I’m sorry people! I deleted my comment about the wear and change rate for parts because I completely messed up conversions between km and miles lol. I can see why people got a bit flustered😂
Advice that still stands:
Wash your bike, it should be clean and make no noise from the drivetrain.
100% agreement on the drivetrain, but what good does washing a bike do otherwise? If you like a clean bike, that’s cool, but what is the performance/longevity reason? I’ll wash mine if it’s loaded down with mud (ie Unbound 2023), but not on a regular basis. I agree with your earlier statement that pressure washers are fine if you don’t direct them toward any bearings (I’d add suspension/shifters/cables/junction boxes, etc.). The problem is that many people aren’t that careful and end up pushing water/grit into a spot you don’t want it. This is particularly tough on MTB’s with pivot bearings and suspension.
I get grit/dirt all over my road bike, not to mention the occasional spills of sugar water or deluge of sweat. Maybe I just like a clean bike, but the idea of spending multiple thousands of dollars on something to leave covered in goo just doesn’t compute for me 
You make valid points about the bearings/seals of course.
A clean bike is a well maintained bike.
I think we’re thinking of this different ways. 6/10 is an effort I can hold for 30-60min. Much like how a VO2 interval feels easy for the first 30 seconds then gets harder, its the same idea for a threshold interval. They both still get the same number for RPE for the whole thing though. I’m rating the overall interval as whole, not the effort at every single instant during the interval.
I don’t do threshold intervals much longer than 20+ minutes as they aren’t really specific to my riding/events, so have minimal experience with how they feel by the end of a 40min one.
By the end of a 2x20 or 3x20 though, I’m usually nearing or maybe a bit over LTHR for the last maybe two minutes of the final interval - it’ll feel like maybe a minute into a VO2 interval. So if you just wanted to label that feeling at only that moment in time, I’d call that a 7-8/10.
A 9/10 in my books is how I feel when I’m going for 1min best power, and that’s not how threshold work should feel.
From what I’ve seen, no direct correlation between the 2.
I know plenty of folks who keep their bikes so clean they look brand new (won’t even ride if it’s raining). But they don’t maintain them with the same passion and/or rely on a shop for maintenance. These are the folks who ride until something goes wrong(ie cable fraying at shifter, running sealant dry in tires, etc.).
If you want a more extreme example, I’ll go back to this year’s mud fest at unbound. So many reports of people replacing multiple crunchy bearings despite cleaning their bikes right after (again, often poor use of pressure washers).
I’m pretty ocd about maintenance, do all my own work except some proprietary suspension stuff. But I generally don’t care how clean my bike is. If trek or Scott want to start cutting me checks, I’d keep them clean, not holding my breath.
I’m not discounting the value of a clean bike for some. If it makes you feel good or faster, that’s a really good reason.
Lots of good stuff already mentioned here, but a few things I haven’t seen are for the most part the bad advice I hear given to my clients. Stuff like:
“This threshold work and endurance riding isn’t what you need; you need to smash short hill repeats if you’re getting dropped on the hills.” from a client’s cousin who raced some track once.
Also tons of bad stuff about riding at low cadence, a lot of it from triathletes who take it way too far, but some from people who firmly believe they’re not riding hard if they aren’t pushing the pedals with higher force, or trying to sprint at 75rpm. Like they forget that the cadence part of power generation is a thing.
Maybe show them a video of -7 spinning his way past Jan, grinding his gears? 
One of the biggest offenders is also a guy who runs around saying stuff like, “You don’t get faster from resting.” and “Coaches are stupid, tapering is dumb.”
I think if your cassette is dirty it will cause the creation of a cutting paste that will cause premature wear of your chain, cassette and chainring. If your rotors are dirty that will cause premature wear of your brake pads. Those sound like direct correlations to me. I am sure I can think of others if you would like.
“She needs to stop eating gels on rides, its making her bonk”
Also something on here: “only the last intervals, when you really push yourself, do anything for your fitness”
The “no rides over 90 minutes until you’ve reached 3 W/kg” stuff is right up there too.
“Endurance makes you slow.”
Had a private sprint coach recruit my cross country / distance runners for indoor track but he wanted them to train with him in the fall ($$$). His sales pitch was that cross county was a waste of time and kills your speed. Admittedly he was a decent sprint coach but knew nothing of how to train for the 800 meters up. I finally convinced one of the boys I had been recruiting to join the XC team his senior year and what do you know… he dropped from 4:28 (where he had been stuck for two years) to 4:13. Not that I did anything magical… we literally added volume, a tempo/threshold workout and paced his VO2 at an appropriate pace.