We like to suggest getting a +2 because it can act a lot like a crystal ball in what the rest of the cycle is going to look like.
If the +2 is about the same as the PS, it's usually going to be a pretty normal cycle....gradually down to nadir and then gradually back up to the next PS.
If the +2 is a lot higher than the PS, that usually means there's a bounce starting and it's usually OK to take a little bit of a break on testing.
If the +2 is lower than the PS, that's your "early warning" that Haley might be going a lot lower later in the cycle and it's important to try to get some other tests in to keep her safe.
TR only requires 4 tests per day, but that doesn't mean you should only get 4....if it's possible, it's better to get tests at different points in the cycles so you can start to get a good idea of when Haley's Onset, Nadir and Duration usually fall along the cycle.
If you can only get 4 per day, then you always get the 2 Pre-shots and then get at least 1 somewhere mid-cycle on the AM cycle (like between +4 and +6) and at least a "before bed" on the PM cycle (usually at least 2-3 hours after the PM shot)