A wedding, an exam, a shop opening. When the date cannot move, the risk is never the shipping. It is the slowest of your sellers.
Most orders have no date on them and the customer is happy to wait. The ones that go wrong are the ones with a date, and they go wrong in a predictable way, so this is the advice we give every time.
The shipping is the part that behaves. Air from our warehouse to your hand has been eleven days on average for two years, and it varies by two or three days. You can plan around that.
The sellers are the part that does not. Every order you place is a separate chance of a delay, and a consolidated shipment can only leave when the last parcel arrives. Five sellers is not five small risks; it is one risk equal to the slowest of them.
So work backwards, and be unreasonable about it.
Take your date. Subtract four days for collection and any island boat. Subtract two days for clearance. Subtract eight days for the flight. Subtract a week of slack, because you will want it. That is the date every parcel must be at our warehouse. Then subtract another ten days for the sellers to dispatch. That is the day you have to place the order, and for a wedding six weeks out it is usually today.
Split the order by risk, not by shop. Order the things that are hard to find first and the ordinary things last, because the ordinary things can be bought again quickly and the unusual ones cannot.
Then consider the insurance order. If one item is essential and its seller looks slow, order the same thing from a second seller as well. It feels wasteful and it costs a few hundred rufiyaa. We have seen it needed often enough that we now suggest it for every order with a fixed date, and the family whose fabric seller went quiet nine days before their cut off used the spare on the tables.
And ask us to ship what has arrived rather than waiting for everything. We will hold a consolidation for you, but if the date is close, two boxes and two freight charges beat one box that misses the wedding. That is your decision and we will always put it to you rather than making it quietly.
One last thing. Tell us there is a deadline when you send the link, not when it gets tight. It changes which sellers we recommend, whether we fly or float, and how often we chase, and all of that is free at the start and impossible in the last week.