The Bible instructs Christians to pray consistently:
Colossians 4:2 (King James Version): Continue in prayer, and watch in the same with thanksgiving.
1 Thessalonians 5:17 (King James Version): Pray without ceasing.
The Bible (unlike the Islamic Koran) does not however give a specific schedule for prayer, so it is largely left to the individual believer to decide. Most Christians would pray when attending a weekly church service, others may attend prayer meetings and other would pray on a daily (or even more frequent) basis.
--->Christians have no set time to pray. They can pray where and when they wish to.<---