The number of spells someone is able to cast in any given amount of time depends on the spell, the caster's experience and energy level, and the tradition of the caster.
Personally, I would never cast more than one spell in a day, though. Not only do spells take time, they take energy. Casting multiple spells in a short amount of time could both drain your energy level and decrease the effectiveness of the spells due to some of them not having as much energy put into them.
Listen to yourself. If you feel like you have enough energy to cast again within a week, go ahead. If you need longer, it's okay to wait. It's better to take the time and have effective spells than it is to force yourself to cast multiple times a day and end up getting completely burnt out.
How ever many you feel you can cast is the right answer. Granted, you need to have enough energy for each one, so if you use up all your energy on the first spell and feel tired by the time the second spell rolls around I would hold off. Also, if you're casting a bunch of spells on yourself for different things [beauty, luck, love, wealth, and protection for good measure all in one day] I would take time off in between to not only recharge but to give the energy time to start to take effect. There's many schools of thought when it comes to magick, but basically sometimes if you get too greedy the spell won't work [like, you cast all these spells to make life perfect, but the gods/universe desire to cut you off to teach you a lesson, or all the energy gets confused/muddy and just fades away] overall, I would either stick to the same type of spells [like Monday only money spells, Tuesday only healing spells] use one of those 7 day candles, or focus on one spell a month.
On the other hand, there is such a thing as mundane magick where you incorporate energy into daily tasks [i do this type of magick] so while you're not setting up an altar with a bunch of ingredients to throw into a cauldron to cast a spell, you can cast a bunch of little spells through your day. A typical one for me would be I wake up, say a morning blessing, I make my smoothie and charge it with energy I need for the day [i have a meeting, I need items with courage] I get dressed and choose colours that correspond with an energy I need [i need more self love so I'll wear pink socks to charge myself with pink energy] while washing my face I'll say a beauty chant for clear skin. When I lock the front door I draw a pentagram to protect my home. At work drinking my coffee/tea/whatever before my shift I'll charge some energy and drink it slowly focusing on charging myself with positive energy [i work with the public so I need to be extra friendly] when I get home I ground myself by wiping away any negative energy on my doormat before entering, during my shower I visualize negative energy being washed away, when cooking I charge my food with energy and choose items that bring a certain energy I want [say it's a special meal for my fiance and I, I would choose herbs/spices/vegetables with love energy] finally before bed i say a goodnight blessing. On their own one of these things aren't "spells" but they are little ways to use magick in my day, so in that way I cast dozens of spells every single day.