The number of yellow leaves does not look alarming to me and could be old leaves dying down. There are no signs of spots on them but I would look underneath to see if you notice anything strange on the underside of the yellow leaves. I would water them less often and longer instead; and do apply about 3-4" of acidic mulch. Their tiny leaves are located on the top 4" of the soil so be careful when putting the mulch down or working around the shrubs.

To determine if you need to water them, use the finger method so you do not end up overwatering. Insert a finger into the soil to a depth of 4" and water (1 gallon) when it feels almost dry or dry; if your soil is sandy then apply 30-50% more water. Water the soil early in the morning with about 1 gallon of water. Make a note on a wall calendar every time that you water. After 1-2 weeks of checking the soil this way, observe how often you had to water and set the sprinkler or drip irrigation to water 1 gallon of water on the same frequency. Then as temperatures increase/decrease by 10-15 degrees and stay there, use the finger method again to see if you need to tweak things.

Go easy on the fertilizer too. Azaleas hardly need fertilizer as they tend to feed off the decomposing mulch. Use some Holly-tone or organic fertilizers like cottonseed meal, compost, manure, etc.

Some wilting is normal in the first year as the plants go thru transplant shock and then become established to your garden. But if the area where they are is windy, that will encourage wilting so consider a more protected location or putting some kind of wind barrier.

Here is a link that might be useful: Azalea Q&A from the Azalea Society

i recieved an azalea tree (approx.)3'tall april 13, 2010. i was told to keep it wet and it didn't need feeding because the florist said it had lots of nuitrients...well, i water (tap water)it every other day about a cup to a cup and a half..how do i know if it's too much water or not enough..evidently i put too much in because some of the flowers are turning brown and leaves and flowers were falling on the floor when i took it out of its container to check it out..do i pinch the dead buds off? i need help to keep this plant living.. i want to keep it in the house if possible year round because of the cold and snow. thank you

You can insert a finger into the potting medium to a depth of 4" to see if it feels dry, moist or wet. Add water when it feels almost dry or dry. Wet soil causes root rot. If this is a florist azalea, it may not do well in Zone 5. Unfortunately, it may not do well indoors either but you can try. Lack of humidity is the problem indoors so monitor soil moisture and keep it away from a/c vents and sunny windows. Top it with some acidic mulch so you do not have to water it often.

Here is a link that might be useful: Growing azaleas