My sourdough starter harvested from the air in middle England 2 or more years ago is now quite reliable. I keep it in the fridge and normally refresh it every week. Some weeks I forget and it goes a fortnight without refreshment. I’ve even left it 3 weeks while I’ve been away on holiday and it revives perfectly.
My biggest learning over this period is to avoid a large proportion of whole flour if I want a good rising. The loaves above have about 80% strong white, with the remainder whole wheat flour, and rye.
I still get a bit thrown off by the rising times which are so different from commercial yeast baking – and sometimes end up baking after midnight.