MacBook Pro question

So, I've had this MacBook Pro for a few years. I use it in my voice work. About 8 or 9 months ago, I started noticing a few things:

1. the machine would heat up
2. occasionally it would hum to the point that I couldn't do any recording
3. the battery ran down rapidly

I had decided to get a new battery and was waiting to complete a batch of work before I did so, when suddenly all of those three problems disappeared.

As an example of problem #3, there were several matches where I'd depart the chatroom at halftime to recharge, and not get back until about 15 minutes left. I could start the match at 95% charged and, by half time, be under 25%. By contrast in the Chelsea debacle on Saturday, I began the match 75% charged and, at the end of the 90 minutes still had around 35%.

Oh, and I haven't experienced any more overheating or noise either.

I'm not complaining, but how did this thing heal itself? I know that Pettyfog is a PC guy, but maybe an Apple vet can let me know what's what?

 

Did the MacBook have any system updates between the problem and its eventual "healing?"

 

That's possible, Senator, if they came in the guise of updates to certain programs. I can't remember anything like a PC service pack 2 in the last few months.

Of course, at my age, I find it hard to remember much of anything.