Moyes is still settling into his post at Old Trafford after replacing Sir Alex Ferguson in June, and some fans are already questioning the club's lack of transfer activity since his arrival.
But the former Everton boss believes a sense of perspective is required as he sets about stamping his own mark at the club.
"If you win one game folk will think you are good. If you lose one folk will think you are rubbish," said Moyes.
"You hope there is a little bit of sense and people understand where you are going. It is a big job. It is a new job. It will take time, as it would for anybody else."
And Moyes is adamant United can compete in the transfer market despite even more competition with the riches now flowing in France at Paris St Germain and Monaco.
"That is not something Manchester United are frightened of," Moyes added. "Manchester United are more than happy to compete with all of the teams.
"There has been a change in the dynamic because of PSG coming on the scene recently. That has altered things.
"But Manchester United will always compete. One thing it has got is the history. It has got the name. It has got the success. That is a big pull for any player."