I don't have much variability in my sales on ebay, except for the boom that happened last year, my sales figures have been pretty consistent for a few years, which is one of the reasons ebay is the testing ground - I've been established here the longest, and pricing is a significant factor in most eBay shopper's buying decisions, so significant changes will be pretty easy for me to see. All of my items have been updated to tracked shipping only - having some untracked at lower cost I suspect would just cause confusion, especially since the majority of sales involve multiple items so people would probably choose a mix of $3 and $6 post items and pay $6 post anyway.

The main test is to see whether sales will be drastically affected, to a point where having postage that is up to slightly more than twice that of some of my item prices, is not sustainable - that part will mostly be relevant to me, as what is and isn't sustainable will vary from business to business, and some businesses can transition much more easily (eg if a business has low value items and most customers are one-off and only purchase one item, this kind of change would affect them very differently, so I intend for this to hopefully just be able to offer some general insight into the effect of switching basically overnight, with some short and longer term insight.

My prediction is that sales of single items will slow quite a bit, but sales of multiple items won't slow as much, however I'll be keeping it in place for at least 3 months, because I expect a lot of people will immediately baulk at the initial change and look elsewhere, but I also have confidence in the fact that I do have some niche products and this will help me over that initial resistance.