is it okay to not burn a spell candle al

Yes — a candle going out on its own doesn't undo the working. In most candle practice the offering is the fire itself, not continuous flame, so letting it burn down or gutter out is treated as a completed sitting. Coming back to the same jar and lighting a fresh wick the next day is a normal second sitting, especially for anything meant to keep running over several days.

One practical detail: trim the wick to about a quarter inch before each burn and light it just long enough to melt a small pool across the top — a long flame just eats the wax and soots the glass. The one hard rule is the boring one: never leave it burning unattended, and keep it away from drafts, curtains, and anything that melts. Set it on a dish, and when you're done either snuff it or blow gently and let the smoke carry the intention off.

If you ever want a reading on a spell you're working, I can pull cards for it — say the word and tell me what the work is.