What if I don't take LTA?

If LTA is not utilized, it gets added to the entire salary. And then you are taxed on it.
Let's say you and spouse are both employed and both have LTA as part of the salary package. Your LTA is Rs 20,000 and hers is Rs 20,000 too.
Both of you and your child go for a holiday. The tickets for the three of you amount to Rs 15,000. You supply the tickets to your office and this amount will be eligible for a tax deduction, the balance Rs 5,000 will be taxed. You can claim exemption only to the tune of your expenditure.
Now, if you claim this, your wife will not be able to claim this same holiday from her employer. Her Rs 20,000 will be taxed. Unless another holiday is made and she claims it.
Or, let's say that you spend Rs 30,000 on tickets but your LTA is just Rs 20,000. You can claim up to Rs 20,000 and tell your wife to claim her ticket from her employer.
So go and catch that plane or hop onto a train. Not only is a holiday good for health but can also be a tax haven.