Don't email the person, it is a scam. [Also don't post emails on the site it's against the rules]
If you feel you have enough energy, you can cast as many as you want. There are a lot of suggestions some feel work but do what works for you. Some feel you should cast by the moonphase because the moon pushes and pulls the energy as it does the tides. Others feel you should cast spells out of desperation or necessity when everything else has failed. Still, some will cast by the planetary hours [a system so confushing for me I've only used it once] basically every hour of every day is ruled by a different planet [Mars, Mercury, Venus, even the sun and moon] this system isn't always the same for every day [the days are also ruled by planets] and it also changes if it's day or night [and if memory serves sunset/sunrise also effects the planetary hours] so, an example, Sunday is ruled by the sun, so the first hour is the sun, but depending on the sunset your first planetary hour could be 12:28-1:28. The whole thing confuses me, but some feel if you cast a spell on the right day, hour, and moonphase for that specific spell, the energy will be the most powerful for your casting.
Personally, if you feel a spell is needed, take a minute and think about it, and if you feel you still need a spell, do it. If you feel you need to cast a spell for wealth and a job spell, go for it, just make sure you have enough energy/focus for both. But if you just want to cast a bunch of spells for fun, you might want to choose the necessary ones or space them out by a day or two.