Is luck an acceptable character trait?
Question: I've tried to balance it out by having my character's luck failing occasionally and just opting for the least likely outcome rather than something that is beneficial but I'm still questioning whether or not everything will seem too convenient. (Also something I think I should mention, This character isn't the main character.)Answer:
You've hit upon the problem with giving a character too much of an advantage. The same thing can happen when you give a character magic powers: if you don't built limits into the magic, you end up with no story because everything is too easy for the character.
That doesn't mean you shouldn't use the character. It's an interesting trait. You just need to balance the advantages with disadvantages.
A classic example is the character Cassandra from The Iliad
. She has the power to know the future, but the limitation is that no one ever believes her.
Another example is the current TV series, Stan Lee's Lucky Man
, in which the main character has a bracelet that makes him powerfully lucky. The limitation is that for every lucky event that happens to the character, an unlucky event occurs in his life to balance it.
So I think you're on the right track by putting limits on the usefulness of the character's luck. Just make sure that once you establish the rules/limits you stick to them consistently. Also, it helps if the limits are as significant as the benefits, and if the magic can be a disadvantage as often as it is an advantage.
Best of luck.