I came up with the idea for Slim Piggy just over a year ago while in the middle of watching a concert (no coincidence, as the comic is essentially about a band) where I had nowhere to write anything down. I remember furiously texting myself character names and the title of the comic between songs so I wouldn't forget. Honestly, out of all the comics I've made in my life, Slim Piggy was the one that started up the fastest... it went from initial idea (December 2014) to it's internet birth on Halloween, 2015.
I had a few comics I actually got going when I was younger, but my adult life has seen a lot more loose ideas and unrealized stories than my kid life. I have one called "Keith Maximum" that came into being from a very bizarre dream about zombies that I had back in 2008 and I still haven't found a proper way to get it going.
So it's a wide range for me... sometimes I can get down to work and start right away, sometimes I kick ideas around and make a few failed attempts at getting things going for eight or so years 
Though it hasn't been long, I keep Slim Piggy going with deadlines and with making sure I love my characters. I keep their stories fresh, make sure I'm flushing out their personalities in my head enough to like their reactions and interactions in the comic. I also think getting it posted on the internet in a more professional way has kept me on track and grounded with the content I put together and put out for prospective readers.
Basically, I put it on the internet to make sure I created it. I feel a more driving force to focus on continuous production and keeping loose when I have a nice place to upload it each week and another place to toss all my sketches and notes and character Q&A's! It's all worked good so far, even if I don't have THAT many people reading it yet, it's still young and I started from scratch with my internet friend-base back in 2014. I'm still happy with it and hope to get it to more people who might enjoy it 
Also, I'm writing about something I love! Which is super important to me. Writing about punk and industrial bands in the 80's and having a good chunk of my characters fit into the LGBTQ+ spectrum keeps ME interested.