What they said ^^^
Note that the maintenance requirements for AGM and flooded cell batteries are quite different:
Flooded cell (conventional lead acid) batteries in vehicles that aren't used regularly can be connected to a battery maintainer (Battery Tender brand are popular, as are solar panels like I use) and should be charged every 4-5 weeks during extended periods of disuse (such as off season storage). They are also vented and the process of charging & discharging causes the electrolyte level to decrease gradually so they need to be checked periodically (the case is usually transparent or translucent so you can see the levels easily) and topped up with distilled water as needed.
AGM batteries are a low maintenance type of sealed lead acid battery. They aren't vented so the gasses produced by charging & discharging stay inside where they recombine into water and topping up is not necessary (the case is opaque so you can't see inside). They maintain their charge for a long time so battery maintainers aren't needed (& can actually decrease battery life). An AGM battery should be fully charged before storage and then left alone for up to 2 years until needed again.
If you are going to use the bike regularly and don't mind looking after the battery during storage an ordinary flooded cell battery is the least expensive option but if you aren't going to use the bike often the price of that less expensive battery plus a battery maintainer can easily add up to more than an AGM.
Welcome to the forum. Please add your location and your bike's model and model year to your profile so that you don't have to remember to tell us every time and we don't have to keep asking when you forget (see Forum Settings link in my signature).
And welcome to the world of antique vehicle ownership (they own us, not the other way around). Your "new" bike is about 4 decades old and may or may not have had all of the maintenance necessary to keep it safe & reliable so it is highly recommended to download the Factory Shop Manual for your model (available through the CX Wiki - link in my signature) and go through all of the service procedures, regardless of whether your bike has reached the specified mileage.
Note that while aftermarket shop manuals are pretty much necessary for people without factory training to work on a lot of makes & models of bike the FSMs for the CX/GL500/650 family of bikes are so well written & laid out that the FSM is really the only book you need and and the aftermarket books are secondary references at best.
I also recommend looking on all rubber parts with suspicion because rubber does not age gracefully. Check the date codes on your tires and replace them if they are over 5 years old no matter how good they look & feel (old rubber simply cannot flow around the irregularities in the asphalt well enough to grip, especially if it is cool or wet). The original rubber brake lines should be replaced every 2 or 3 fluid changes (= 5 or 6 years) so if your bike still has them I recommend shopping for modern stainless braided ones (they last practically forever and double the life of the fluid). And don't forget things like the rad hoses and the boot between the engine and swingarm (they can crack on the bottom where you don't see it).
