OK, I finished my taxes and am annoyed that I'm getting a refund (mostly to a change in state where I work). That said, I have a firm rule that 10% of any unexpected money goes to something non-essential. This keeps me from snapping and spending it all.
So, I love my Litter Robot 4, it's completely awesome. Do I splurge and get a reconditioned Feeder Robot? (I have three cats and OMG the Litter Robot has been life changing.)
Side note - for those of you considering the Litter Robot:
I have three cats. I used to empty two litter boxes twice per day with a complete litter change monthly. I used a 32 lb bag of WBCL per month at $30.
I've used one bag every three months and empty it once per week since going with the LR4. I consider that to be positive ROI. YMMV.