Qitzur Shulchan Arukh – 67:3
One must be careful not to make a neder about anything [i.e. any object]. Even for tzedaqah it is not good to make a neder. Rather, if he has something in his possession which he wishes to give, he should give it immediately. And if he doesn’t, he should wait until he does have, and give it without a neder. If they [some group] are pledging tzedaqah and he must pledge with them, he should say explicitly that he is pledging without a neder. Similarly when they remember souls [i.e. say Yizkor] that they vow money to tzedaqah, it is appropriate to say “without a neder“.
Also see ahead, se’if 9, that if he is in a time of trouble, he is permitted to make a neder.
“Speak little, and do much.”
The sole exception appears to be when someone needs merit now, and therefore wants to make a commitment in a time of need. And even there Rabbi Ganzfried says “permitted”, not “laudable”.