Praise be to Allah.
Singling out a particular time or place for doing an act of worship that is not prescribed in any Islamic text, without believing that that time or place has a particular virtue – rather it is something dictated by circumstances, so that he needed to do it in that particular time or place – has nothing to do with innovation at all, and there is nothing wrong with it. Rather innovation or introducing things into the religion refers to cases where the aim is to add this innovation to the teachings and prescriptions of Islam, or where that is the likely outcome; in that case the Muslim has fallen into innovation.
Dr. Muhammad Husayn al-Jeezaani (may Allah preserve him) said:
There are three characteristics of religious innovation by which it is known to be such. A thing is not regarded as innovation in religious terms unless it meets these three conditions. They are:
1.Being newly invented
2.This newly invented matter begins to be regarded as being part of the religion
3.This newly invented matter has no basis in Islamic teachings, either in a general or specific sense.
A particular practice may be regarded as an innovation when one of the following three things applies:
1.The practice is aimed at drawing close to Allah by means of something that He has not prescribed
2.The practice drifts away from the general guidelines of the religion
3.The practice may lead to innovation.
End quote from Qawaa‘id Ma‘rifat al-Bida‘ (p. 18-23)
But as for doing a particular act of worship regularly, at a specific time or in a specific place because circumstances allow doing it at that time or in that place, without believing that one must do it then or that there is some special virtue in doing so, there is nothing wrong with that – as in the case of one who fasts on Tuesdays, for example, because that is his day off work; or one who regularly prays qiyaam on Friday night, because he is off work on Saturday; or one who regularly reads Qur’an between Maghrib and ‘Isha’, because he has free time then; and there are many similar examples. All of that is permissible, because no innovation is being introduced into the religion in these cases, and it is not something that could lead to the introduction of new innovations.
Shaykh Ibn Baaz (may Allah have mercy on him) was asked:
What is your opinion on what some imams do of specifying a particular portion of Quran for every rak‘ah and every night?
I do not see anything wrong with that, because the matter depends on what the imam sees fit. If he thinks that it serves a purpose to increase the portion on some nights or in some rak‘ahs, because he feels more energetic and thinks that he is able to do that, and he sees that he is enjoying the recitation, so he increases the number of verses in order to benefit himself and benefit those who are praying behind him, so if he beautifies his voice and begins to enjoy the recitation, and he feels focused, then he and those who are praying behind him will benefit. So if he adds more verses in some rak‘ahs, or on some nights, we do not think there is anything wrong with it. The matter is flexible, praise be to Allah, may He be exalted. End quote.
Majmoo‘ al-Fataawa (11/335)
Based on that, we do not see anything wrong with giving charity regularly on a particular day because circumstances allow that, to the exclusion of other days, and not because one believes that there is a particular virtue in doing that on that day.
And Allah knows best.