I try to be conscious of dynamics, and I wish I had the strength and stamina to wreck a keyboard. Seriously though, I've kept the velocity curves at factory default, thinking that they are intended to mimic the action of an acoustic piano.

Factory default does not mimic the action of an acoustic piano for everyone. It does for Norm, but not for Cliff, Fraser, or Woody...

The Normal curve might be an average but nothing says, forgive me, that you’re normal. We all have a different touch. They only seem to contradict each other because you are setting an overall response using the Velocity Curve. If you are heavy handed (and I’ve found that those who are rarely realize it). They wind up with 127 velocities dominating their Event Lists, there may even be tons of Aftertouch data all over their Event Lists. This is a person not having fun. They are not fully utilizing the dynamics of the instrument.

So the very first thing you need to find is the general Velocity Curve that matches your particular playing style (it’s okay not to be “Norm”...) set this so that you have an overall response that matches your approach. The keys are not delicate, they are made to be played. You should see the robotic ‘fingers’ that put these keys to the test!! To break a key while playing is rare — typically, it gets mashed by some foreign object in the road case, a speaker falls off the wall and lands on a key. A four year old takes a hammer or other foreign object and starts pounding out a lick. Normal playing, in theory, should not break a key. (We have tons of keyboards in the field for 10, 20, 30 years or more with no broken keys.

They do break but there is usually a cause (not related to normal play) could simply be a bad part, that does happen - But no one likes to say (admit) that they abused their Keyboard. So it’s silly to even argue the point (they will always say “it just happened”... ) The various actions over time have a track record... at Yamaha we’ll stand by that track record overall.... spend some time talking with any keyboard tech to get an overview of keyboard reliability... but when you get a person that says they “always break keys”... (again no one wants to say “lighten up, dude” but making the appropriate adjustments including the Velocity Curve, and Output Volume will usually stop this from happening. Once you have the appropriate Velocity curve... the heavy handed need to increase the effort to get Loud... then you turn the sound system to the appropriate LOUD level — once you’re there; where you get the sonic response you desire without beating your keyboard to the repair shop, you’ll know.

What you want to avoid is the wrong Velocity Curve and the wrong Output Volume! yikes!
If your heavy handed and your Curve is soft (you’re reaching 127 way too soon, and then imagine you can’t hear yourself so your banging mercilessly at the keys. Yikes!

The deal about how loud you make your speakers is offered because most musicians are lazy... this I find is particularly true when electronic instruments are involved. They will adjust the Volume and not their playing approach. This can adversely affect what gets documented. Ever record your string parts as MIDI, only to discover that the audio level is way too low when you attempt to render Audio?

This can be in either direction.. not enough velocity or way too much. Only if you make your speakers as loud as an acoustic piano in that same room will you hit it with the appropriate touch. With your Velocity Curve set correctly, and your Volume up where it should be, even the heavy handed will not beat their keyboards into repair.

Hint: call up a Tone Wheel Organ sound (B3) Record yourself to Cubase or any DAW where you can see velocity values... then ask yourself: should there be any 127s on the page? If there are... you just might be a heavy-handed player.

But if you are playing a forte acoustic piano passage with little effort your cheating the wrong way. And if you are banging too hard it’s equally wrong.
Mostly the heavy handed put too much weight into playing and because their sound system is not loud enough, they wind up banging out too many 127s... by turning the sound system up... they will naturally use the appropriate weight to play.

It’s different for each player... in the recording studio watching piano players trying to hear themselves in headphones, if the engineer sees them banging on the keys, by raising their level in the headphones, it will cause them to stop banging. They naturally adjust their playing to how well they are hearing themselves.

If your recorded results wind up with way too many 127s or way too much Aftertouch... admit it: you’re heavy handed.
This is not a bad thing - it only becomes a bad thing if you don’t make the appropriate adjustments.
Heavy-handedness can eventually break weakened keys (no doubt) but there is a cure if you “always break keys”.
Heavy-handedness should not break keys on a well adjusted keyboard. Especially, a Yamaha!

Also, rather than analyzing MIDI streams to "see" if 127 velocity is reached - you can setup a Part to play a whistle sound (think police whistle) on any key and only when 127 velocity is reached.

Rather than sifting through data, you can just hear the keyboard whistle when the highest velocity is reached.