Significant gifts to benefit others through viable non-profit programs should never be “impulse buying”. This is also true of “impulse” increases to organizations you have been supporting who are pitching a new product or major expansions if you increase your giving.
Buy a new sports car on a whim and if you decide later you don’t like it, you will generally be able to recover a good portion of your investment. The same might not be true for a charitable gift and it will likely take you a lot longer to realize you made a mistake. Meanwhile, programs you would have been delighted with are unknown to you and delivering results you had hoped for but haven’t realized in the program you “bought” too quickly.
Having said that, we all need impulsiveness and impatience now and then or nothing new happens. If you are anxious to make a difference and have the resources to make it happen, investing in the independent research they way you would when buying a property or a new car makes sense. Donor fatigue often is a result of not doing enough work up front and listening only to the sellers.