There's been a few times in the past where me and many other players started grinding a tank line right before a Top of the Tree/On Track event came out, causing us to unfortunately waste millions of credits. So I decided to create a list of all the "Top of the Tree/On Track" events in recent years to show which tech tree are least likely to get upcoming discounts so you can grind them.
For the most part, it takes a tank line over 1-2 years before it gets rotated again for a Top of the Tree event. HOWEVER, there have been a few rare exceptions of tanks lines being rotated in a year or less with the most outlier example I can find being the Japanese Heavy line (Type 5 Heavy) which actually had TWO "Top of the Tree" events in the same year with only 7 months in between each event (Jan. 2023 & July 2023). But for most cases, it should be safe to grind a tank line if it was On Track within a year ago without worrying about upcoming discounts/sales.
TLDR: In 95% cases, all tank lines from this year's events shouldn't be getting a discount soon.
As of now for 2023, they are USA: T110E3, T110E4, T110E5, T57 Heavy, and MVY UK: Badger, Cent AX, and Manticore German: Leopard 1, Rhm PzW, Maus, and JgPz100 Russian: Obj. 140 and T100LT French: BC25t and Foch B Chinese: WZ-132-1 and WZ-113GFT Japanese: Type 5 Heavy Swedish: Udes 15/16 Czech: VZ55 Italy: Rinoceronte and Minotauro.
