Tether deposit checklist: pick the network before you copy the address
A short route from holding Tether to sending it, in the order that avoids rework. The order is the point: the network is chosen first and everything else follows from it.
Start on the sending side
Open the screen you will send from and look at the networks it offers for Tether before you open the casino. That list is the real limit on your choice, because a casino can accept five routes and your wallet can offer one.
If the list is short, the casino's list only has to contain one of its entries. If the list is long, you have room to pick by fee and minimum.
Match the labels, not the look
Operators spell networks differently. One writes BNB Smart Chain where another writes Binance Smart Chain, one writes TRON where another writes TRX - Tron (TRC20). They are the same networks. Matching means matching the network, not the exact letters.
Always match the network you select with the one supported by your deposit wallet before you proceed.
Do not match by address. An address of 0x and forty hexadecimal characters looks the same on Ethereum, BNB Smart Chain, Polygon and Avalanche.
Copy, then compare the ends
Copy the address the cashier shows for the network you chose, and copy the memo if the screen shows one. After pasting it into the sending app, compare the first and last six characters with the cashier. Truncated displays hide the middle of an address, and the ends are where a mismatch shows.
If the cashier changes the address after you change the network, that is correct. Each network has its own.
Send a small amount first
A small first transfer proves the network, the address and the memo together. It costs a second fee, and it is the cheapest check there is when the amount that follows matters. Wait for it to be credited before sending the rest.
Short answers
What is the first thing to check before a Tether deposit?
Which networks the sending side offers for Tether. That list is the real limit on your choice.
Does a small test transfer settle which USDT network to use?
It costs a little and settles whether the network, address and memo are right before the larger amount goes.