Speaking from experience, you can be reliable as clockwork if the conditions don't change. The hard part is deciding how to react to changes in light and temperature and humidity. If it's a climate controlled situation and the light is good, you can and should water on a schedule. Otherwise, use your discretion. The goal is to wait until the soil is dry before watering. There is no particular benefit to leaving it dry for any extended period, but these plants do better with a lot of air in the soil on a regular basis.
I like to water well (until water comes out the holes in the bottom) and then wait until the soil is dry at depth before I water again. The surface layer will dry out much sooner, so it's not a reliable indicator. You can try putting in your finger or a chopstick or a moisture meter, whatever works for you. Or judge by the weight of the pot, as you like.
I can't tell what the problem might be with the succulent in the original post. I'm guessing there is a problem in there under the dead leaves, like some rot in the stem or maybe the roots have let go. Does it release from the soil if you tug gently? Try removing the dead leaves for a good inspection of the nether regions.
It looks like there are a couple of shoots at the top which may grow bigger, so definitely don't give up until you see what happens there.
Was it totally healthy when you got it? Did it undergo any sharp changes in light or temperature? Is there good air flow in that location? Does it experience any kind of greenhouse effect? The south facing window ought to provide good light if it's unobstructed outside. You might get away with watering every 5 days if it's warm and dry. You might try weekly otherwise, this time of year.
