The Spain international, 29, has often been a substitute this season, despite consistently impressing and using his undoubted influence when selected.
He has often appeared off the bench to change some of Chelsea's more difficult games after his manager's preference for the combined physicality of N'Golo Kante and Nemanja Matic.
His starting of their past two league fixtures also means he could again be selected for Saturday's game at Stoke, but even with Eden Hazard, Kante and Diego Costa playing so well, Conte is adamant Fabregas should not be overlooked.
Conte said: "Cesc gives you great quality, great fantasy and assists.
"It's important to manage the situation and understand when it's right, for example, to play with Cesc or with Matic. We are talking about two great players, with different characteristics. Nema is more physical, more technical, less fantasy than Cesc; Cesc has more fantasy but is less physical than Nema.
"He has always had a great impact, whether he starts a game or comes on. He always has a great impact. He's technically very good, and can put the ball where he wants. He's a great player. Often he's decisive with the pass, with the assist, and also to score a goal.
"This season, he has improved a lot in all aspects and, for me, he is a really, really important player."