1) It is correct for a person to accustom himself never to make a vow. If he did make a vow, it is better that he should go to a wise man to repeal the vow, rather than keeping the vow and fulfilling it. Chazal said that one who vows is considered as if he has built an altar in a time and place where one is forbidden to build such an altar, and if he then fulfilled the vow it is considered as if he had offered a sacrifice on the altar, when by so doing he will have transgressed the prohibition of offering sacrifices outside the holy temple. (Kitzur Shulchan Aruch 67).
2) However, this law (that it is correct to ask a wise man to repeal the vow) applies only to regular vows, but there is a commandment to fulfil vows for holy things, as it says “I will fulfil my vows to Hashem”, and one should not ask a wise man to repeal them unless there are extenuating circumstances. (ibid).