It started off with a slight trickle that you can barely hear if you're nearby and by week 2, it had worsened to a stronger and continuous streaming that I could hear all day from my home office which was a room away.
I did score a good deal for Kohler Genuine Part Gp1138930 off of Amazon for $15 and got the husband to replace it last Friday.
Thankfully, it wasn't a big job, he was done in around 10 minutes.
P.S. I was honestly amazed at how fast the husband completed this job. I consider myself handy around the house (relatively) but anything related to toilets make me nervous because of that unfortunate incident when I accidentally cracked one while trying to update the lever.
I still avoid any toilet-related repairs even though it has been 13 years since then.