Have you ever wondered how long it has been since you turned of your Macbook or it had a full reboot instead of the usual close lid when finished using?
To check your Macbooks uptime open Terminal which can be found in Applications->Utilities and type
uptime and press enter/return
You now get your Macbooks uptime, an example of what might be returned is
up 89 days, 19:16, 3 users, load averages: 1.89 1.95 1.95
This Macbook has been “on” for 89 days 19 hours and 16 minutes. Meaning it has not had a Shutdown or full reboot for that length.