when doing a spell and it says something like...you need three blue candles, does it matter what the size of the candle is if the spell doesnt specify, i know there are those tea light candles..the really tiny ones, then theres those stick candles, then just regular thick, tall cnadles, so if you were to use one tall one and two tea lights, would it make a difference, seond question, can you use a candle more than once? like if you have a candle you already used can you use it again for a different spell?
As far as I know, no. I usually use whatever size I have on hand and my spells/rituals turn out just fine. If you use a candle for protection, I would only use it in other protection spells just because that is the purpose you blessed and charged it for.
Also, like with most magical tools, you don't need to use candles in rituals or spells. Tools are, more or less, used to help yo better focus on the goal or intent you have for your spell or ritual. If you feel you need them then use them, if you don't then don't use them. The choice is entirely up to you.
About how many times to use the candle must be indicated in the text of the ritual.
Typically, a candle in the ritual dogovorat to the end. One ritual - a new candle.
If a ritual is done for several days, it is permissible to use the same candle every day ritual.
sometimes (in the text of the ritual) is required to leave the small remnants of candles. Stubs are at a crossroads at night and there seems to pay off.
More important addition: the candles should never be cut into several pieces! If you need a little spark - do it yourself