I’d probably go with
IF(
{Days Until Event}>31,
IF(
{Hours From Last Check}<-160,
"yes",
"check"
),
IF(
{Days Until Event}>7,
IF(
{Hours From Last Check}<-71,
"yes",
"check"
),
IF(
{Days Until Event}<=7,
IF(
{Hours From Last Check}<-36,
"yes",
"check"
),
"check"
)
)
)
(I think that evaluates as you intended.)
There may be some clever ways to short-circuit it, thus eliminating redundant "check"
s, but maintainability is perhaps more important than conciseness in this instance.