I had the same Garmin 510 for years. I can’t even remember when I bought it. I was careful with the battery. Rarely discharged it fully, maybe five times in the years I had it, so it lasted quite well. I can still make a century with the old computer using the route navigation. I can’t, however, make it a century using the route navigation and my Varia blinking light/radar. That’s just a touch too much. If I turn the navigation off after 80 miles or so, I’ll make it home with only a few percentage points of battery life left. If I include a heart rate monitor, fuhgeddaboudit.
And that’s why I finally upgraded to the 530.
The 530 has several bells and whistles the 510 doesn’t have, including closer monitoring of the battery life of both the head unit and my radar/blinkie and the ability to control the operation of the functions of the blinkie. The 530 appears to double, approximately, the battery life of the 510.
The 530 operates much the same as the 510, but cleaner, prettier, longer and better. In my own personal opinion, the 530 looks like Garmin’s way of saying, “Look, Bob messed the 510 up in the design phase so we fired him. The 530 is what we should have done with the 510.”
Anyway, with all of the bells and whistle add-ons for the Garmin computers these days, you really need the battery life of the 530. All of the cool gadgets made the 510 obsolete… or excellent for shorter rides. If you’re into the long stuff, 50 to 150 miles in a day, the Edge 530. You can pick one up for $300 US, or less if you search the webz for about .000162 of a second.
Don’t forget, if you get one, to set it up properly. The indoor setting doesn’t use GPS, so don’t change that activity profile to something outdoors where you’ll need the GPS enabled. Also, I duplicated the road profile for a gravel road option rather than change the mountain biking profile. Don’t forget the auto-pause feature. You’ll want to set that for all of your activity profiles. Then, it’d probably be wise to consult the operators manual to set up your Varia. You have to get the sequencing just right so you can choose the mode you like the light to stay in (I always use daytime flash because it saves on the battery).
I’d liken the 530 to the road sport cyclist, the gravel cyclist or the mountain biker. You’ll need some battery life, but you won’t need that 400km brivet battery life with a computer smart enough to choose the best route to get you to the finish on the fly. That’s the 1030 and we can leave that one to the adventure cyclists who typically have no idea what “too much of a good thing” means.
Fit Recovery 
Someday I need to get one, hopefully the mount is easy to put on other bikes, I ride 5 different ones.
Some mounts are easy to swap out. Others, not so much.