I think this is a good, honest question that comes up from time to time, so i'll cut and paste my past two responses:
"When will spells work, or when should i see results from my magic spell or candleburning?
"I was taught to look for magical results in a grouping of three: three days, three weeks, and three months.
"Within three days of the work, you should stay open to any omens or signs, positive or negative, about the status and outcome of your intents. These could take the forms of chance happenings, a sign or statement from a stranger, a dream, and random events that have meaning or relate somehow to your working. Be on the look-out for these early signs - they're always there.
"By three weeks you should have definite, observable movement. Things should be starting to or in the process of unfolding either toward your goal or away from it. You should have a little more than signs; you should have some results.
"In most instances, after three months you should either have what you desire, it should be within arm's reach, or you don't. There are a few exceptions in the instance of chronic and severe problems, long-standing conditions, and excessively stubborn situations and people.
"If you do not have what you wish after three months, do some soul-searching. Re-evaluate your intent. Is it towards your best nature? Do you have any doubts? How can you re-work it? Then try again or move on.
"For long-term magical work it is absolutely necessary to set a deadline. This is most true for reconciliation work which has a tendency to drag on and on with little windows of hope, then disappointment, more time, etc. In prayer ask God/dess or your Higher Self for a deadline, a firm time where you will work your hardest to obtain your goal, but after this date, whatever it is, if you still don't have what you want, you will give it up and move forward. This is such important advice; i pass it on whenever i can."
Copyright: Me, LdyGry, A HIgher Source Spiritual Supply
And in response to an inquiry about re-doing spells on the same target...
"I will cast the same spell for the same person or circumstance twice and that's all. I will chalk up one time to an error or not enough oomph, and will give it just one more go. Then if i don't have my desired results after doing the same spell for the same circumstance twice, i'll let it go or rework it entirely.
"Doing this work professionally for years i have seen what happens when people get obsessive about a certain type of spellwork - especially reconciliation spells or love spells on a specific person. This is not an instance when more is better. If you haven't gotten your goal in two spell workings, it's most likely isn't happening.
"I will give spells three months to manifest. If i haven't gotten significant results in three months, i will not expect results. Of course there is the rare exemption.
"I was taught to look for things in groupings of three: three days after the spell watch for signs and omens, three weeks (or sooner) watch for movement, three months (or sooner) watch for results or no results. Using this formula, say after three weeks there's no movement at all or negative movement, then i won't wait the entire three months and i'll either redo the spell or rework it."
Hope that helps :)