As a complete beginner it’s easy to be confused when youtube and other people tell different answers to the questions I have, I’ve done plenty research but I’d rather hear from people who have actually been through the process to get a better understanding.
I’m a newbie too - I thought it was pretty quick for them to get the inventory, maybe 2 weeks. Seller Central is your friend. You can track your shipping progress on Seller Central (I shipped them myself). You will also see your inventory there. It is a little confusing because some my inventory says out of stock but available (?), but when I go to my store as a consumer, it shows the inventory is ready to ship - I can add it to my cart so that’s a head scratcher for me. How much to replenish, depends on how much you sell. The inventory info in Seller Central calculates how much days of inventory you have based on how fast you are selling. That and lead time will help you decide when to reorder. Good luck!
Replenishing inventory is a delicate balancing act. Many things factor in: manufacturing lead time, shipping length and port delays, Amazon overstock fees, etc. One way to help mitigate the challenges is to keep a limited supply at your residence. That way you can quickly replenish in a pinch and not run out of inventory. Hope this helps.
Generally, shipments can take anywhere from a few days to several weeks to be received by Amazon, depending on some of the factors already mentioned above. If you’re using Amazon’s partnered carrier options like UPS, it might be quicker due to the established logistics and agreements between Amazon and those carriers.