After the first password change, your browser or phone will probably offer to save the Tigerexch password. On a phone nobody else touches, saying yes saves pasting next time. On a family laptop, say no.
Saved passwords are filed by address. Store yours on tigerexch.ai and then open tigerexch.club, and the boxes come up empty, because the browser treats them as two different sites even though it is one Tiger Exchange account behind both. Save it a second time if you use both addresses. Annoying, but harmless.
A remember-me tick is a different matter. Some sign-in screens show one and some do not, and we have not checked it on every Tiger Exchange address, so it is safer not to rely on it.
Two people, one phone? Each needs a separate number, because the counter turns down a second ID on a mobile that already has one (the Tigerexch ID rules explain why).