See previous posts; already asked and answered.
However, as you didn't get it before, let's try again.
For the new pilot seeking his or her first 135 job under VFR, 100 hours of cross country is required. For IFR, 500 hours of cross country. It's very possible that many applicants who have been flight instructing, flying skydivers, doing tours, or other things to get to their requisite 500 or 1,200 hours for that first job...won't have 100 or 500 hours of cross country time if they simply use the 50 nm rule.
For the pilot needing to meet the qualifications of 14 CFR 135.243(b)(2) or (c)(2), then the cross country definition provided under 61.1(b)(3)(i) applies. This means demonstrating cross country flying not beyond 50 nm but simply between two points with a landing at a point other than the point of departure, and involving some form of navigation.
On the other hand, for the individual seeking his ATP, the cross country provision of 61.1(b)(3)(vi)(b). This means that a point other than a point of landing isn't required...but a straight-line distance greater than 50 nm is.
Depending on one's particular requirements, then the classification and applicability of the time logged change. Certainly there exists a valid reason to log cross country time when the distance does not exceed 50 nm. Do you understand this?
