Some simple advice on Yucca care

Yucca are pretty hardy plants, and so long as you exercise some common sense and are aware of the basics you should be fine.

If you sit your Yucca in direct sunlight it should stay pretty compact, as it'll be getting all the light it needs. The less light they get, the more they stretch towards the light source.

As Yuccas age it's quite common for black spots on the leaves to appear - don't panic, it's not fatal. Try to remove the blackened areas if possible, or, failing that, just remove the whole leaf. If the whole head becomes 'unsightly' simply cut it down a bit and wait. Yucca's will take pruning like this in their stride and grow new, healthy heads. Make sure you don't over water the plant during this time though, it has less foliage, and so needs less water.

Watering:

Yuccas are durable, and can tolerate being dry, so don't panic if you go away for a while and there's no one around to water it. The rule of thumb seems to be to check the soil, and when it dries out it's time to break out the H2O.

Under-watering will show - the leaves will turn yellow and/or brown, and the stalks will shrivel up.

Similarly, over-watering will also show - although I've never seen it, over watering a Yucca results in the leaves having brown tips, with a yellow 'halo' around the tip.