Mid-2012 MacBook Pro Battery Health
So its now 2018 and my 2012 Macbook Pro has been starting to show it's age recently. My more current problem is the battery health. I used Coconut Battery checker to keep an eye on the health of my original battery (which is not "Apple" but another company "Simplo". My battery is at 747 cycles and working at 68.3% of its original design capacity. After reading around, I've seen that Apple's OEM batteries are supposed to last 1000 cycles before they break 80% design capacity which is obviously not my case. Is this a common occurrence? When should I consider replacing my battery? Currently writing this as my battery health is 5% after going from full charge to this in under 3 hours of light use. Would appreciate any input or ideas to what I should do. Thanks!
MacBook Pro, macOS High Sierra (10.13.4)