How do you track shifting brand loyalty in CPG without blowing the budget?

Honestly, repeat-purchase panels on Numerator or even a quick survey on Pollfish ($200-300) asking 'what did you buy last time vs. this time and why' can separate true switchers from deal-hunters fast. Look at whether they're buying your brand on promo vs. off-promo — if loyalty tanks when deals stop, that's your answer. Household panel data is the gold standard but if budget's tight, even a 300-person pulse survey with purchase frequency questions gets you pretty far.