With a brand new starter, I keep it on the counter and feed it 1:3:3 twice a day for about a week. I've probably used it to bake a few times. See below for my video!
If I plan to keep baking - maybe twice a week, then I'll keep it on the counter but will drop the ratio down to 1:1:1. I've found that it does keep the starter alive, maybe a little under-fed, but still ok. If I plan to get a loaf of bread ready, then I'll build the starter the night before at a 1:3:3 to bulk and muscle it up. Then when I use it to make a Leaven the next morning, it's strong and ready to go.
If I'm baking 1 x a week or less, then I'll put the starter in the refrigerator and leave it there, feeding it 1:3:3 every 7 days or even every other week. If I plan to bake, then I take it out the morning before and feed it twice that day at a 1:3:3 ratio. It wakes up nice and bright, comes back strong every time.
Starters last indefinitely with minimal attention. IF - IF for some reason your starter develops fuzz or anything pink or orange tint type color, you should pitch it and start from scratch. That's happened to me only 1 time in about 10 years. It's a rare occurrence.
An under-fed and starving starter will develop more acid which can collect on the surface as a brown or grey liquid called Hooch. Some people pour this off, as it can be strong or bitter and super boozy smelling. But - if it's not too boozy, I'll pour off a bit and stir the rest in. It makes for a tangy bread. If you really like tang, consider using some of that hooch.
I hope the video below helps you!