Welcome, kellychiu! Very nice sketch, well done! 
To me the time is merely a ballpark, really. It’s good, but it’s also nothing that would stop me from a flow, which is why I normally should stop while I’m ahead, haha. When ever I don’t…well…the above happens and I go over a few minutes. But I have cats and am constantly interrupted anyway, hahaha, so it should all be good.
However, when you’re in the zone, enjoy it and don’t let the time put you under stress! 
…worked out just fine for you, though!
Welcome, mantiz! That’s awesome, too, really nice style! At least one of us had to take the topic for it’s expected meaning, hehe. I love the details in it, it’s fun to explore your painting. It could’ve gotten a bit more controlled contrast for foreground and background to avoid it from becoming flat, I enjoy the well improvised perspective, which is kinda sweet. Altogether…Great job!
(All those flasks and liquids must’ve been a bit tedious to make, really nice!)
Glad to have you both here!