Logic 9 asked me for Registration Code again 6 years into owning it

Hi all, I've owned Logic 9 for however long it's been out (5-6 years?) on my 2009 MacBook Pro 17". About 2 weeks ago, I tried to open it, and it asked for my registration / serial # to unlock the software. As if this were the first time I was using it. Luckily I still have the booklets and the serial / registration # for my copy of the software - I entered, it worked, and I have since had no issues.

However, this has made me nervous. I'm concerned this could happen again at any point, and if it does, my serial / registration code may not work again (I've now used it twice - once initially 6 years ago and again when this happened couple weeks ago).

- Why after 6 years and hundreds of times opening the software did it "reset"?

- If this does happen again and my registration code doesn't work, will I be able to fix this? Will Apple provide an auxiliary code?

- Has anyone else experienced this?

- How many times are you allowed to install the same copy of Logic 9? I vaguely remember when I bought the software it said you could install it on up to 3 computers (and I think it even specified 2 laptops and 1 desktop), but I could easily be mistaken. I ask this also bc I'm in the market for a new comp and I should def be able to install my copy of Logic on it, but with this I'm worried it won't let me.

Thanks for your help!