The Personal Finance wiki from that other site has a Prime Directive flowchart that spells out how you should allocate windfalls. Here’s the US flowchart but they have them for other countries with their respective finance programs.
In short, if you already are able to live off a smaller income, build an emergency fund so you don’t go backwards, then pay your future self. Don’t inflate your expenses unnecessarily because that just makes the goal of retirement cost more in the end.