Clothes - whenever something has holes in or no longer fits or can't be repaired. Buy quality the first time and it lasts! Usually only by new in sales, also shop in charity shops for only the brands I like, very occasionally.
Shoes - as above. I treated myself to a pair of ankle boots in October to replace a pair that I had to bin at the end of last winter (after 5yr wear).
Make-up - foundation and mascara whenever they run out. Worn every day.
Jewellery - I last treated myself to a pair of silver studs for £3 in 2022. Before that it was in 2015! Received decent and fairly spenny jewellery from DH for birthdays however.
Watches - mine last purchased in 2012. £20. Still going strong. Prior to that, my last watch was purchased in 2002.
Hair cut - twice a year.
Nails - not done since 2019. Occasionally paint myself.
Spa days / facials - couple of times a year.
Girls weekend away - couple of times a year.
Meals out - every couple of weeks.
Coffee shop treat- 2 or 3 times a week.
Everyone has their own way of treating themselves! Mine is with food and beverage 🤭