Even before we even had children, one of my wife's non-negotiables for raising kids was that we would have all kinds of instruments just available for them. She didn't want to compel lessons or make them a project. She just wanted them present so the kids could pick them up when they felt like it.
This is probably one of the smartest things we've done as parents because our kids are getting pretty deeply into their music to the point I'm already jealous of their ability to express themselves and they basically just started.
Our oldest son is extremely detail-oriented and fidgety, so when he found the piano these tendencies became like superpowers for him. Our middle son, the one with a dangerous amount of charisma, has recently become obsessed with the guitar.
And the oldest translates piano music into guitar riffs for his little brother.
Our daughter, the youngest, hasn't really locked onto anything specific yet. She likes the drums and the piano and the guitar and the idea of the violin and she sings. But she's 6 so she's doing exactly what she should be doing - and exactly what her brothers did at her age. Just trying things out.
Both boys are now taking lessons because they explicitly asked for lessons - not because we "put them in lessons." We just let them play for fun, answer their questions, and provide them the resources they need (instruments, music, accessories, etc).
But at 8 years old each of our boys has independently gotten serious about mastering his first instrument.
Our oldest son practices 2-4 hours a day and arranges his own music. He is already better at the piano than I've ever been at anything in my life. (This was his first piano recital at 10 months if I sound too hyperbolic.)
And his little brother has only recently started really focusing but he's an absolutely instinctual natural and will be sure to put me to shame in a similar way. He's gonna shred and break so many hearts.
When we talk to the kids about their music my wife and I always key on how hard they're working, but also make sure that they know our love and approval are not contingent on them "continuing" or "achieving" - but that if they love it, we think it's wonderful and will do everything we can to support them.
We are absurdly careful not to pollute their love of music, so we don't push them. Sometimes we ask them about their goals and then help them think through what they could do next to achieve that next musical goal, but we never drive the conversation. We encourage, but never require or even cajole.
It comes from them, always. And, now that I'm thinking about it, I have a hard time thinking of a more valuable meta-skill we, as parents, could be teaching them.
And it all stems from simply having the instruments around.
Idle, available instruments are surface area for sparks, and we just want our kids to have as many sparks in their lives as possible.