More laptop battery replacement advice
I assume that this is the first time you have had the need to replace your laptop battery. Others have reported (on this site) that by the time it came to replace their laptop battery – the particular model replacement battery was no longer available. The reason for this is that the laptop manufacturer no longer produces a laptop model having the same physical size battery and/or electrical contact arrangement.
With no market for the battery, production is discontinued.
You could consider buying two batteries (with one as a reserve), but I would not recommend this since after 3 years of inactivity (charge/discharging) the battery is likely to be no good.
If your current laptop is likely to meet your needs for a few years yet (and you use it for extended periods on battery power), then regularly check the availability of the battery on a number of sites. Once the battery begins to become scarce, purchase a replacement and consider regularly swapping the batteries to avoid the new battery sitting around unused for an extended period.