Do babies lose or gain spots as they grow up?

I always see the "before and after pics" of how babies lose their spots and markings as they grow up, is it common for the light markings to fade, or is it a 50/50 for the markings to develope into black spots?

Here is a baby I got on 8th Aug, he was 12g then:


The markings on his head was pretty light, and I thought maybe they'll fade when he grows up; there were also very small, faint black dots on his body.

Here is him now, he's now 33g:


As you can see, all the markings and small black dots have turned solid black and enlarged. I am wondering if the development of spots is due to my husbandry or is it just the way it is? He's in a 10 gallon by himself, and he spend most of his time at the cool end (~78-80F).

Is there anyway that I can tell whether a gecko is beginning to gain spots or beginning to lose spots?

[Side note: I really love this little guy, but I think he hates my guts... everytime I walk in his room, he'll stop doing whatever he's doing, and SLOWLY walk back into his hide! I can sense him thinking "mama is ruining my fun!(sigh)"]

It's perfectly normal that your gecko gained spots instead of losing them. It's all in the genetics.

Some geckos gain spots and some loose them. Genetics is a big part of it but also temperatures can change the appearance of the gecko. If it’s too cold or hot the colors dull out and the spots seems to be more pronounce. Photo documentation is the only way I can think of to tell whether they gain or loose spots.

Beautiful leo by the way!