Sha’baan is certainly a virtuous month and for which Rasool Allah sws said that ‘Sha’baan’ is my month. Sha'baan is characterised unlike the other months in that (except for Ramadhaan) the Prophet (sal-Allaahu `alayhe wa sallam) used to fast more in Sha'baan than any other month . So he used to either fast all of Sha'baan or just a little. Therefore, as long as it does not cause difficulty for a person, it is befitting to increase in fasting during Sha'baan in adherence to the example of the Prophet (sal-Allaahu `alayhe wa sallam).
As far as 15th if Sha’baan is concerned; what maximum could be said about this day is that ‘it is like any other 15th day of other months. If a person is in a habit of fasting the 13th, 14th and 15th of every month then certainly he should also fast in these days of Sha’baan.
Nothing firm and reliable has been established on the authority of Rasool Allah sws that he sws stood in prayers in the night (Qiyamul Lail) and fasted specifically during the day of 15th Sha’baan.
In Saheeh Muslim it is narrated that Abu Hurayrah (may Allaah be pleased with him) said: “The Messenger of Allaah (peace and blessings of Allaah be upon him) said: ‘Do not single out the night of Jumu’ah for praying qiyaam and do not single out the day of Jumu’ah for fasting, unless is it part of the ongoing regular fast of any one of you.’”
Further to specify the giving of sadaqah on the night of the 15th of Sha'baan every year is an innovation and one should avoid it.
 Fataawa Shaykh Muhammad Ibn Saalih al-'Uthaymeen - Volume 1, Page 190
Muhammad ibn Saalih al-Uthaymeen al-Wuhaibi al-Tamimi (1925–2001 CE) was one of the most prominent Islamic scholars of the latter half of the twentieth century. Born in Saudi Arabia, he memorised the Qur'an at an early age and studied under some of the most knowledgeable scholars of the time including: Abd ar-Rahman as-Saa'di, Muhammad Ash-Shanqeeti, and 'Abd al-'Aziz ibn Baaz. During his many years of study, he became world renowned for his superior knowledge in fiqh, eventually compiling over fifty books on the subject.
 Noorun alad-Darb Fataawa Shaykh Saalih Ibn Fowzaan - Volume 1, Page 87
Dr. Sheikh Saleh Al-Fawzan, born 1933, is a well known scholar in Saudi Arabia and prolific author. His surname is also rendered Fozan or Fawzaan.
After the completion of his doctorate, he was a teacher at the faculty of Sharia at his alma mater before being transferred into the department of the fundamentals of religion, or Department for Higher Studies within the Faculty of the Principles of the Religion (usool ad-deen). He was later the head of Saudi Arabia's Supreme Court of Justice.When his period of headship their came to an end, he returned to teaching there.He is currently a member of the Permanent Committee for Islamic Research and Fataawa, Saudi Arabia's highest religious body, a member of the Council of Religious Edicts and Research.
 The Permanent Committee for Islaamic Research and Fataawa (al-Bid'u wal-Muhdathaat wa maa laa Asla lahu - Page 611)
The Permanent Committee for Islamic Research and Fataawa is an Islamic organization in Saudi Arabia that issues rulings in Islamic jurisprudence (fiqh). It consists of the most senior Sunni scholars of fiqh in Saudi Arabia.