I understand the sentiment to encourage low impact living, but many younger forum members may find that frugal living, good market returns and an independent lifestyle leave them in a situation with more wealth then they need.
In that situation, a modest luxury, like a pool, should not be a horror. We should enjoy the fruits of our labor and not feel obligated to donate any spare penny to charity. This is especially true if one spends wisely (e.g. vacation with full travel hacking, homestays, etc.). Each of us should be confident enough with our own choices to support well reasoned decisions. Buy that iPhone 10, if you REALLY want it, can afford it, and the value is worth it to you.
No outside person should judge our individual choices once FI is reached (IMHO).