I don't travel, so my discretionary spending might be a little less than yours.
Social Security, my mini-pension, and my RMDs all come to my bank account on a monthly basis. At the end of the month, if I have enough for something I want, then I buy it. If I don't, I wait.
Normally if this develops into an unspent excess in my bank account by the end of the year, I invest it at that time according to my planned asset allocation. I seldom if ever sell any of my portfolio and withdraw it; money goes in, but not out.
In the unlikely event that I wanted to buy something extremely expensive, then I might leave the excess there in the bank and let it accumulate until it was sufficient. That's what I did during the 4 years when I was looking for my Dream Home. Once I found the right house and paid for everything in cash, well, that took care of the excess in my bank account plus a little more that had accumulated within my portfolio. After the house purchase I went back to investing the excess in my bank account at the end of each year and not selling any of my portfolio.
