We are faced with certain social quirks unique to this technology saturated age. One being: receipt of an email from someone who says yes thanks for the interest and promises they’ll try to give you what you want/find what you’re looking for. To this you could reply in kind immediately with a thanks hope to hear from you soon, cheers. Or you could opt for a long delay in response, with the rationale that getting back to them months later has the advantage of reminding them of what it was you asked of them, if they had forgotten. Otherwise, if you answered immediately, as is almost expected with email, and they subsequently forget, you would be obliged to initiate a new message reminder as soon as it became apparent that they had forgotten. This latter method might be interpreted as rude, as it insinuates they forgot about you or that you think you are more important than their other business, whereas the delayed response can be excused as having been incredibly busy with more pressing needs and the underlying motive of reminding cannot be proven to exist.