How much generosity is too much?

Generosity seems like a trait that would fit well into your theory of moral amplifiers. But how does one best deal with someone who is being overly generous? I recently relocated to a new city and one of my coworkers with whom I am friendly has really gone above and beyond trying to help me get settled. She is constantly offering to help, lend me things, or even give me things to make life easier. I appreciate her offers and turn down many of them as politely as I can. But I struggle to find the right balance of accepting her generosity in due proportion to our friendship. She seems to be fairly wealthy, so I don't think her offers are sacrificial in any way, my issue is that we are friends, but not close enough friends to justify the incessant barrage of motherly offerings. Through consistent communication about what I am willing to accept and what I won't -- and also owing to actually getting settled in the new city -- she's backed off a bit. More broadly, how would you recommend dealing with this sort of problem? How can a person make sure not to make this mistake of being overly generous?