I'm also guilty of many chages.
Right now, I'm noticing it on my actual game (codename: Vendetta Project). I've learnt so many things about code, and graphics, that even now that the GUIs are all established and running smoothly, I'm having new ideas for new and more efficient GUIs.
And I say to myself: "Holly mollars! You should save those ideas for the next one, G."
Also, I startes doing quite simple graphics for one mere reason: to save time. Right now, I find myself sometimes making a hiper-detailed room, and I stop fot a moment.
And I say to myself: "Holly Cosmos, G! You're making those full-detailled scenographies again!"
Even the characters start to look more dinamic, and right now my main character looks stiff and boring!
And I say to myself: "Holly Gauacamole! I'm going to remake the sprites of the main character"
So, yes, this is a common phenomenon.