Witchipedia

No there is nothing bad that will happen. You want to try different approaches to the same effect. Just because one way will work for me, it doesn't mean you will have the same result. Write spells down, and you might have to edit some and try again. Then try a different spell. Rinse repeat.

For example. If I'm in a hurry I'll just do a sigil. But if I'm doing a full ritual I'll do a sigil, carve sigil into candle, bag, and verbal spell for what I want to happen. And than I'll do the next spell. So no, please try all you can think of. A certain spell that you do might work better then the previous one for what you want. And experiment. Push yourself. Dream big.

It really depends on what spell or ritual you go through or use. I will usually have a warning at the bottom or top of the page. If not then it will say in the spell of you are useing and of you energy or aura, and even if you do go through anyways it will probably just make you tired.

"Magick is the science and art of causing change to occur in conformity with will" - Allister Crowley
Magic is science, and scientifically speaking the magic that witches perform is the moving and pushing of energy, and that magic is fueled through / energy is controlled by intentions. Technically a spell can be performed without anything other than a concentrated mind and clear intention. The "spells" we perform are sympathetic representations to help give our minds something tangible to go along with our thought forms. (not to say that spell ingredients don't have added benefit, such as plant spirits that lend their own energetic power).
So there's something to be said about feeling the need to perform a spell multiple times for the same thing. If you've already made up your mind that a desired outcome isn't going to work after the first attempt and is going to need multiple workings than your spell is most likely not going to work. You need to perform your work as if your desire has already manifested. Powerful intention can outshine candles and rhyming words any day.
In regards to money and prosperity work, it is common to keep an altar so to speak. So you could set up a money or prosperity altar (nothing official as the name altar implies, it could possibly just be a small space on your counter or in a corner of a room on a shelf) with an appropriate candle (green obviously in this case), with objects used in prosperity magic (which you probably are already aware of and have sense you've been doing the spell work). Monday is the day to do money and prosperity work, so you could work your altar every Monday - anointing the candle with money drawing oil, lighting appropriate incense, and such. These types of works can be done every Monday for an indefinite amount of time, or you could start your work on a Monday under a waxing moon and perform the work daily for seven days as the moon grows. Likewise you could start on a new moon and perform the work through the moon cycle, ending on the full moon.

But more than anything, have confidence that your magic is going to work so well the first time that you will never have to repeat the spell again. Intentions are very powerful.