I (the developer) started a small staffing company in early 2019. I found that everyday I was writing down to-do's. For the day, for the week. Even for the month.
I was filling up entire notebooks with this stuff. Sometimes I wouldn't get everything done in a day and I'd re-write the to-do on the next page of "today's to-do's". Sometimes I'd forget, and I'd realize several weeks later, that I had overlooked something important.
Eventually, I had enough. I'm a fairly tech-savvy person, and I thought there must be a more efficient way to do such things. So I took a week off from work and built the prototype for the to-do list app of my dreams.
I started using it everyday and began honing it into the tool it is today. I showed other friends, and more people started using it. Eventually, 'Planit' was born.