If it's means tested then it's not UBI. Sickness/disability might indeed be a problem, but it's better to address that specific problem, eg. with health care subsidies, rather than reintroducing means testing. Means testing has three major problems:

1. Incentive to game the system.

2. Social stigma to receiving benefits.

3. High administration cost.

UBI is the only welfare system that eliminates all three.

> Most discussions I've seen of UBI recently have shifted from universal to means tested.

If it's means-tested, it's not a UBI; the “U” is ”Unconditional” (less often “Universal”, with the same meaning) indicating that everyone in some defined population gets it without means, needs, or behavior-testing, specifically.

> Regardless, wouldn't UBI need to be higher for the sick, elderly, and disabled?

With a UBI, existing benefit or social insurance programs that aren't primarily means tested but address other special needs might need to be maintained, including programs offering special support for the aged, blind, and disabled.

This is different than a means-tested safety nets, though.

It can't be means tested, both philosophically - the U - and practically, since to make the numbers work (in the UK at least) you need to also ditch the expensive bureaucracy.