All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
The Prophet used to swear in order to emphasize important matters, for instance he said: "I swear by The One in Whose Hands my soul is…", the scholars concluded from this Hadeeth that swearing is permissible without asking [or obliging] someone to swear by Allaah. However, one should not swear too much, especially if the person who swears is not sure to fulfil his oath. Allaah Says (what means): {But guard your oaths.}[Quran 5:89] Furthermore, Allaah blamed those who swear too much as He Says (what means): {And do not obey every worthless habitual swearer.}[Quran 68:10]
Therefore, swearing too much is a reason which could lead a person not to expiate for an oath he failed to fulfil. What is even worse than this, is to swear by Allaah on a lie, and this is what is called a Ghamoos oath, which is an oath that plunges one into Hellfire, and it is one of the great major sins.
So a Muslim should advise whoever swears too much, as the essence of religion is advice.
Allaah Knows best.