While succulents are native to arid regions and generally thrive in poor soils, this does not mean one should not water them or provide nutrients.
There is no answer that is universally correct. There is a direct relationship between water, light, temperature, soil conditions and humidity. The higher the light level and temperature and the less humid, the more often watering is required. Most cactus and succulents have an active growing period for about a third of the year. During this active period, watering can be frequent and fertiliser should be applied. The most active time for most cacti is during the spring and early parts of summer. As this period passes, it is best to reduce the frequency of watering as winter approaches. They require very little water during the cold months. A good watering once a week in hot weather and once a month in the dormant period is a good point to start as you learn your plant’s needs.
Too much fertiliser can be worse than none at all. Use a low nitrogen fertiliser at about a half to a quarter of the recommended rate.
Most commercial potting soils are too rich in fresh organic matter for these plants. The most important factor in choosing a planting medium is that it allows food, water and air to get to the roots and is porous enough to let water drain through. Many growers use a mixture of a low peat planter mix and pumice (50/50). Sand, small pebbles and vermiculite are ingredients added by many successful growers and hobbyists. Experiment with different combinations to discover the right combination for your conditions.
A top dressing of crushed granite or pea gravel looks good and has benefits as well. It keeps the topsoil from drying out faster than the rest of the soil in the pot, keeps the base of the plant dry and assists in the even distribution of water.
Direct sun and light are not the same! Succulent plants need light, but they grow better if they don’t bake in the midday sun. In the wild you will find young plants tucked under a bush, tree or something else that provides filtered light. If new growth on your plant is pale green and elongated, it needs more light. If the side of your plant facing the light source is yellow, tan, red or indented, it is getting too much light.
Succulents do not like stagnant air. Provide good air circulation for your plants.