McNamara left Partick Thistle in February to take over from Peter Houston at Tannadice, and helped the team to another top-six finish.
But his arrival on Tayside also gave McNamara the chance to assess his squad as he looks to make progression with United next season.
McNamara said: "Coming in when we did has been a good learning curve for us by getting the chance to see the players.
"It's better rather than just coming in now when the season is coming to an end.
"We've seen the players day-in and day-out in training as well as games. Now we know what we have to do for us to push on next season."
McNamara admits it will be the end of the present campaign before he makes a decision on the future of defender Marcus Tornstrand, who joined United on loan at the end of February.
"We'll sit down with the players at the end of the season," McNamara added. "Marcus hasn't featured as much as he would have liked. There have been different players playing in front of him in his position.
"We hadn't seen a lot of him before he came in and in terms of fitness as well, it was his pre-season. It's been a big ask for the lad to stake a claim right away."