I ride 15k a year also. My tires are tubed tires on spoke wheels so I've resolved that I'm simply NOT going to be making a roadside flat repair. Cellphone/credit card is the solution there. It can be done with a tube, but it's very complicated, involved, and just not what I'm going to do on the side of the road. A plug kit is a good idea on a solid (non spoke) rim with tubeless tires. (By the way, my 900 uses tubeless tires, WITH a tube in them!)
In addition to a credit card and cellphone I carry 2 or 3 small, plastic, disposable rain ponchos. A particular brand I found that DOESN'T flap around in the wind. I also carry rain gear, a small change of clothes (gym shorts and a t-shirt). That all goes in a small bag in one saddlebag. It's there in case the weather gets really bad, or I get stranded. I don't use the plastic ponchos, those are for traveling companions. I've probably given a dozen away, and always keep a few. They are like 2 bucks a pop and work really well.
In the other saddlebag, I carry a small multi-tool, an extra knife, some zip-ties, some elastic and rubber straps, and that's it. Whatever I can't fix with that can get fixed at the nearest shop. That still leaves plenty of room for clothes, laptop, camera, you name it. I know punch likes to travel light; but I take everything I want
Plenty of storage if packed well. On a long, multi-day trip, I also take along a 'mechanics socket set' I have, Crafstman brand, that is a single wrench, extension, and a full range of sockets. If I was really minimalist I could just pick out the sockets my bike uses and put it all in a bag, but that works. I can make larger repairs there too. I've never used it on my own bike, but used it once on a friends. He had a Dyna at the time (an Ultra Classic now) and his shifter just came apart in tons of little pieces going down the road, it was weird. We pulled into a gas station and I used sockets, a knife, and zip ties (and the help of two other friends) to get him a semblance of a shifter to get us home. We were almost home anyway. He just had to shift a few times to get on the highway, and a few times when getting off. (We had a nice twisty last-leg home planned. But, we're good enough friends to suffer the interstate for him! Ha!)
I'm with you on being prepared but as to carrying spare parts? I don't think so. Tools, sure, spare parts, nah. A spare bulb seems reasonable but they rarely fail, honestly. Generally only one side (high or low) is going to fail. Your vaquero doesn't really have any cables. There's a small throttle cable that goes to an electronic throttle system, without much tension. But the clutch and brakes are hydraulic. There really isn't anything that's common enough to warrant carrying.
Oh, and like Scott said, first aid kids come in handy! I keep one of those on my bike too. So far (thankfully) I've only used it for minor "roadside repairs" off the bike. Insect stings, small cuts, etc. Stuff I got out and about, nothing on the bike!