Don't set a deadline for a deal or offer and then plan to extend it at the last minute.
Some marketers have latched onto this idea as a way to turn up the urgency pressure on customers. Force customers to buy before a deadline, then give others more time, all as a way to squeeze out more sales. It's not much more than a lie and a bait-and-switch.
It might work once, but once customers catch on they won't be fooled again. News and especially negative opinion travels faster than ever. This is how you train customers to never buy unless there's a massive discount.
Better to come up with a new offer than to risk customers thinking they were manipulated.
Learn which products build the best customers
Find which products create the most valuable customers with the First Product Analysis in Repeat Customer Insights. It goes beyond your best sellers by looking at long-term purchasing and retention behavior of your customers.