Many carts but few purchases: review checkout or product page first?
I have been reviewing a natural cosmetics shop for a few weeks and something has me a bit stuck. On mobile, products are added to cart at a decent rate, but out of every 100 carts only around 18-22 turn into purchases. Traffic comes mostly from Meta, average order value is EUR 36, free shipping starts at EUR 49 and returns are simple, although that part is barely visible until the footer. I do not want to change half the site blindly. If this happened to you, would you start by reviewing the product page, checkout, visible shipping cost or trust before payment?
I would look at the exact step where people drop, not at the average. If there are many carts and few payments, separate opened cart, checkout started, shipping seen and payment started. In many shops the hit comes from discovering shipping too late. Test a small line above the button with "free shipping from EUR 49" and, below it, a short line on exchanges/returns. I would not make it a huge banner, just visible before the decision.
Something similar happened to me and the issue was not checkout, it was the product promise. People added to cart because the photo and price were good, but real size, texture, who it was for and how long it lasted were missing. When we clarified that, add to cart dropped a little but final purchase went up.
If average order value is EUR 36 and free shipping starts at EUR 49, I would test a "you are EUR X away from free shipping" module inside the cart. But be careful: if it pushes weak or forced products, conversion rises and then returns or complaints rise too.
I would not touch design first. I would record anonymized sessions or review events for 48 hours. Sometimes it looks like a trust issue and then it is a shipping selector loading slowly or a payment button stuck under the mobile keyboard.