i agree. with any investment, it's all about speculation since we don't have insider info. luck also helps
i'm stepping onto my soapbox now.
while lego sometimes indirectly drops hints (e.g. sets keeping selling out, set is getting long in the tooth, sets that like to be replacements are released, buying limits per order, etc...), it is still mainly speculation and luck.
i assume sometimes we need to go with our gut feeling. as some of us (at least me) are both AFOLs and collectors , i like to think those people have a grasp on what sets will be popular after retirement. my honest opinion, it's not rocket science and people shouldn't depend on the same repeated posts about what sets should be bought.
if i think a set is totally cool after building it, i'm buying it since others will probably feel the same way after missing out on it. that is why people jumped all over 10226 SC, 10221 SSD, 10228 HH, 10197 FB and even sets back in the mid-late 2000s like 10179 MF, 10196 GC, 10181 EF and the first 2 modular blgs to name some. To me, they were totally awesome builds and looked cool on display
10224 fits into my thought process.
bottom line is to not wait too long in buying sets you think are cool.