Edit: Has anyone used this - https://www.aliexpress.us/item/3256804913368665.html
Or am I better off with old school wear indicators?
I have a similar one from another brand, Toopre, but it wouldn't surprise me a bit if it's all same manufacturer just different brand logo on it. Ztto has it too, other brands also around Ali.
Mine works well, but seems the only advantage is being able to check when it's 'beginning' to wear (between 0 and 0.5), which is not a big difference
since replacing is with 0.5 or 0.75 wear, the old school indicator will do just fine.
Yeah, deals are not really widespread... It seems that every sale there are less sellers participating...
same here, I was looking into radars (Bryton R300 and Magene L508) but neither are in good deals, and most of the stores are not offering them within the sale discount.
I have the same impression, less sellers/products getting in the sale, and also the discount used to be bigger, and for higher amounts. Like, at least for Brazil, it's up to 12 usd off $90, but last year for example I have bought stuff with 24 off $240, even higher on previous years. Discount for expensive stuff, not only the cheap items
Maybe there are too many sales happening, it's like every 2-3 months there's some sale going on, so this is probably a small one and the big stuff will come only in 11.11 which is the biggest sale of the year
Order now or wait? Is there a good discount on it... or will it become even cheaper during the campaign week? does anyone have any experience? 
it actually doesn't follow a pattern. Sometimes the coupons only work in the beginning because they're limited, but there are cases in which closer to the end more coupons were released (or renewed).
In my opinion, if the price seems good then go for it. There's always the chance of a better price in future sales, like the 11.11 I mentioned above, but u'll have to wait 2.5 months.
one thing you can try is offline payment, it works as some kind of 'order reservation', but I think it depends on the country and payment too so you have to see if it's available for you
like, here in Brazil, I can place the order as payment by wire transfer, and I have 72h to make the payment or the order is cancelled. Through that time, the order is there waiting, and I can pay by credit card if I prefer, change the payment mode at will
Also, and this is maybe the best, I can choose the pay the whole order or just from specific stores.
So it offers not only some extra time to think about the order, but also if you want all items
