Because azaleas bloom in spring, you cut them back immediately AFTER they bloom. If you prune now, you could potentially cut off the flowers buds for next spring. Wait to prune after they bloom next year.

I assume you are referring to a tropical hibiscus (vs. a hardy perennial hibiscus). Indoor plants often don't get enough light. Be sure you are placing your plants in the brightest light possible. Being old plants, they may also benefit from being pruned and re-potted. Pruning prompts new growth and re-potting plants enables you to start with clean, fresh soil indoors.

Start by pruning each plant about to about 1/2 - 2/3 of its current size. This will make repotting easier by reducing the size of the plant. Cut branches to just about a leaf node (the point where a leaf bud emerges). Take this opportunity to improve the plant form too - remove awkward looking branches and branches that are tightly crossed. Removing some internal branches will allow light to reach the inner canopy of the plant and improve leaf and flower production.

To re-pot:

1. Choose a pot with sufficient drainage holes (at least 3) in the bottom and about 2-3" larger in diameter that current pot. Also choose a large saucer to place underneath the pot to keep your floor clean / dry.
   
   
2. Purchase an all-purpose potting soil labeled for indoor plants. Note: don't use / buy bags of soil that have been stored outside as they may contain insect pests. Carefully remove the plant from the pot. Take a look at the roots - they should be white and firm. Remove any roots that are mushy / brown. If the roots are tightly packed together (a sure sign repotting is needed) then gently work these loose before re-planting.
   
   
3. Add soil to the bottom of the new, clean pot and set the plant in the pot. Check that the soil surface of the plant is about 1-1 1/2" below the rim of the pot. This will allow for sufficient watering without overflowing. Holding the plant in place, fill around it with more soil, tapping down the soil as you go along. The plant should be planted at the same soil level as previously - in other words, don't plant the hibiscus deeper in the new pot.

Once you have filled the pot, water to settle the soil, and place the plant in a sunny window. You may see some leaf drop due to re-potting and also due to the change from outdoors to indoors. This is normal. Also check the plant every few days for insect issues and treat as needed.

Check the plant every few days for water needs by feeling the top few inches of soil. If the soil is dry, water until water drains out the bottom of the pot into the saucer. When new leaves / buds start to appear (signs of active growth), add an all-purpose indoor plant fertilizer every two weeks to your watering. Use it at half the recommended strength to prevent excessive build-up of fertilizer salts.

Feel free to reply with additional questions.