How much do you think you will need to live on, monthly, when you retire?
I live in a poorer part of Europe, and, as my mortgage will be paid off and I have no debts, and if DC have finished studying, I think I could be comfortable on 1800 euros take home per month. It's rather unlikely I will have that amount (this isn't the best place to plan financially), but something to aim for.
What about you?