here in SEAsia the usual used word of attachment is the same as for being in debt. Something "normal" but good if seen, of which is not so normal any more.
It's good to try to help, it's paise-worthy to feel not only obligated, and it's also a sign of integrity to be willing to pay back and be not in debt. Thoughts, doing and effort, even physical, by speech and body, doing what ever possible, all of that is skillful.
It's how ever not in ones sphere in how far another might receive gifts, receive repayments. Sometime one can do what ever he/she might be able, but another is either incapable or unwilling to take.
That's then the point where one needs to let go, or better do not hold on that strong. Beings are owner of their kamma (deeds), so there is no way to what others anything to do and any gain is a result of previous or present deeds at least.
So at a point it's good to not only switch to mudita (having joy with what good another has done) but also metta (release with a wish of goodwill).
It's not wrong to forward goodness to others and also a way to solve ones obligation and to stay open in all directions with ones generosity and open hands in regard of needs and wishes of others.
Only one who has reveived goodness, has become aware of what sacrify means and that they are done by others, is not only capable to develope goodness him/her self but also to become a grateful person.
At least, don't forget, real teacher and people of goodness do not take any rewards but let you only one way open to "pay" off your debts, and this is by becoming a great person by your self, infect others in same way and make not only yourself but also others part of another economy, that of giving and letting go, leading to heaven and beyound.
For having gotten a good "The Lessons of Gratitude"
Blessed if not and not becoming a (self-called) modern or western Buddhist who actually use Dhamma only to deny their duties and waste their past merits, incapable of goodnesz, gratitute, generosity and becoming people a integrity, striving after wrong or pseudo liberalism and dwell in hypocracy. Something one should always be careful not to fall into since there is less liberating in becoming a careless consumer of past done merits. Rejoice with your good qualities and that of others and try to stay as often by wishes to repeat good mind states, for that is the case of gaining right release by right concentration caused by right lack of remorse, fundemental debtlessness.
"And what is the treasure of generosity? There is the case of a disciple of the noble ones, his awareness cleansed of the stain of stinginess, living at home, freely generous, openhanded, delighting in being magnanimous, responsive to requests, delighting in the distribution of alms. This is called the treasure of generosity.
Dhana Sutta: Treasure
Only a person seeking for ways to do good will find possibilities, only of what is nurished an improved will grow and increase and as the Buddha often told, it's seldom to have goid possibilities, so one should be quick in actions of good deeds and like Nissaya search after them, for such is the cause to Upanissaya and to come near the path of the Noble Ones, step by step.
One is not wise if just waiting of what old merits and possibilities come along and eat them just away. Yet of course one can also not makes one good deeds undone and not to ripe, so their is no fault in receiving good and clean gifts of others on the way. Steady, in ways of giving and receiving, increase the qualities of "food" up to heavenly and food for beyound of all burdens of exchange.
Then, when the tanks is really empty, that is where the Buddha told householders, having done the highest duties, one may seek seclusion and use the release for working on fruits beyound obligation.
For a person of integrity possibilities of fulfilling as well as chances to give at fist place are a source of joy, having conviction or even know the results of a joyful and open handed mind all time prepared to give and let go. Such a person never lacks on anything needed and conductive. Give it a try to be shameless in regard of doing skillful all the time, by thought, speech and deeds, where ever be. Devotion toward the proper is not a burden but right means to release.
[Note: This is a gift of Dhamma and not meant for commercial purpose or other low wordily gains by means of trade and exchange.]