[Deal tip] When to actually buy stuff in Japan — Rakuten/Yahoo point days & June timing

Been in Tokyo a while and finally cracked the "point economy" here. Quick notes for this month: - Rakuten: the 5・0のつく日 (5th/10th/15th/20th...) plus お買い物マラソン stack points up to 10x+. - Yahoo! Shopping: certain days give 20%+ back if you pay with PayPay. - Drugstores (Welcia etc.) have point-day combos too. For daily stuff (detergent, rice, diapers) I stopped paying full price and just stockpile on these days. It's not flashy 半額 sales, but over a month it adds up a lot. What deal apps / tricks do you all use? Always looking to learn more.