When a chart comes to you for it to be judged, first look if the native has any malefic karma that is impacting his life. The prediction given by an astrologer can make the native take a different life line than what was intended by his karma. When a malefic karma for the native is huge and astrologer gives predictions, then on karmic transaction level, the astrologer takes the native’s malefic karma in exchange for the positive advice. This is why an astrologer needs to be very cautious when judging many charts day-in and day-out.

When a chart comes to you, right at that moment, create a Prashna chart.

A Prashna chart always depicts the karma up until that moment of casting time.
If the Prashna chart is created for the querent, it shows the karmic debts related to the querent.

Viswanath

Now, coming to our question

How to check if you need to study a chart?

Visti Larsen, whom I see as one of the inspirators for me, gave a very beautiful tip on this topic.

Always check the 12th house in the Prashna chart. If there are many malefic influences in the 12th house, then the native has much bad karma and any consultation at that point, by reading the native’s chart, will result in exchange of that bad karma by the astrologer.

Visti Larsen

Now, malefic influences can be from natural malefics like Saturn, Mars, Sun, Rahu and Ketu by:
(1) aspecting the 12th or
(2) occupancy in the 12th or
(3) owning the 12th or
(4) in conjunct with the 12th house lord, occupants or
(5) having any connection with the 12th house lord or occupants at the Star lord or the Sub lord level (if this horary is casted per the KP system, else this point can be ignored.)

In such, scenarios it’s better to advice the querent to do any japa related to his Ishta Devatha and come back at a later time.