According to Responsys, retailer email frequency during the holidays is at an all-time high - averaging 5.6 promotional emails a week in the most recent week.
A common question I get from clients is "how often should I email my customers?" My default answer years ago used to be "once a week" then over time it turned into "no more than a couple times a week" and now I try to dodge the question altogether...
The uncomfortable reality is that in my experience, the incremental revenue gain from sending another promotional email outweighs the measurable costs or risks. "Uncomfortable" because none of us want to say that it's "ok" to pound customers with promotional messages every day. But given the volume of messages flooding inboxes these days, there's no question that the odds of your emails being seen at all are directly proportionate to your send frequency.
Regardless of whether you're an online retailer, the same context applies. There's a single inbox and it's no longer about monitoring what your "direct" competitors are doing, every company out there trying to reach that same consumer is your competitor.
I have seen very few case studies showing the positive impact of reduced send frequency (a couple mentioned in this blog - for UK version of Open Table and luxury retailer Net-a-Porter). Frequency testing is complicated, but it's the only way to truly gauge what's right for your customers and for your business, from both a near-term and long-term perspective. And don't forget to keep an eye on seasonality.
If the holiday season (or Mother's Day or Back-to-School) isn't a key revenue driver for your business, why not give yourself a break instead of trying to compete with the seasonal senders. And if it is a key selling season for you, well...you have the data points.