My starter has been going for about 2 1/2 years now. I use 50g old stater, 75g water and 75g fresh strong organic white bread flour (but you could use any flour, like spelt). I put it in the fridge and refresh once a week, though i have pushed it for 2 weeks.
When i go to use it, i will get it going over a few days. I have one of these cup warming plates which can go down to about 24 degrees c. I then make up the starter and put on plate. Refresh 24 hours later. I do this for a couple of days, refreshing every 24 hours. Then refresh every morning and evening for a few days. It will be very active by now.