Sitting isn’t easy, so setting a specific amount of time to meditate helps me maintain a consistent practice. I started off using a kitchen timer, but it ticked, so an audio-engineer friend created “songs” for my iPod with a gong at the beginning, silence for 10, 20, 30 or 45 minutes, and then a gong at the end. This was in 2006, a year before the first iPhone was released.
When I bought an iPhone in 2011, one of the first apps I downloaded was Insight Timer Light. I upgraded to the paid version later, for the advanced options. I can’t remember what it cost, maybe $9.99, but it seemed like a reasonable price to pay for an app I used almost every day.