Luke 18:1

Now [Jesus] was telling them a parable to show that at all times they ought to pray and not to lose heart.

Ephesians 6:18

And pray in the Spirit on all occasions with all kinds of prayers and requests.

There is no time that those who believe in Jesus should not pray.  There is no place that the believer in Jesus should not pray.  There is no occasion at which a believer in Jesus should not pray.  Never let anyone tell you any different because that would not be from God, but from the evil one.  So pray!

Blessings,

Pastor Dave