1. श्रीमद्भगवद्गीता (अध्याय 17, श्लोक 20):

दातव्यमिति यद्दानं दीयतेऽनुपकारिणे।
देशे काले च पात्रे च तद्दानं सात्त्विकं स्मृतम्॥
That gift which is given out of duty, to one who does not return the favor, at the proper time and place, and to a worthy person — that gift is considered sattvik
2. manu smriti
शक्तितोऽर्थं प्रयच्छेत् पथि भूते धनेष्वपि।
न हि सन्धार्यते नित्यं वस्त्रं वा यदि दुश्चरम्॥

One should give wealth according to one’s capacity, especially to travelers, living beings, and the needy. Wealth or clothes are not to be hoarded forever — they must be used righteously.
3. as per Mahabharat
शक्तितश्चैव यो दद्यात् काले देशे च साधु च।
न तेन तुल्यं पश्यामि यं नान्यः कोऽपि मन्यते॥

One who donates according to his capacity, at the right time, in the right place, and to a virtuous recipient — I see no one equal to such a person; none else is so highly regarded.

यथाशक्ति दानं पुण्याय भवति।

Giving charity according to one’s ability leads to merit

always do that much as per the situation and need is