Mac Battery
My 2013 MacBook Air says service battery and keeps randomly shutting down. I already reset the SMC and the cycle count is only at 529. What should I do?
MacBook
Have Apple replace it while that option remains available: Mac Service and Repair - Official Apple Support.
I think your Mac remains supported. Eventually, Macs are considered "vintage" which limits Apple's ability to service it. After that, your options become both limited and expensive.