How often to run various tests, and how long do you run your filter?

[waterbear]

But the question was "how often do you test"

I viewed the question as one with a 'universal you' as in meaning "How often should these things be tested" and not as how often does each individual answering the question test, which is not going to be valid for the OP as your case clearly demonstrates.
Personally, I know my TA and CYA stay stable because I have a cart filter so I only test those evey few months but I do test my CH every two to 4 weeks because the level tends to drop faster than the previous two parameters (I have soft water and a fiberglass pool and have seen first hand that higher CH does help prevent stains in fiberglass.) However, this also is not pertinent to the OP.

Ditto for how long to run the pump. How long either you or I run the pump doesn't matter but the OP will need about 10-12 hours a day with her Intex pump/filter on a 5 k pool.