Andy Murray says he needs to find a "permanent solution" to his coaching situation if he is to make any significant progress this year.
Murray parted with Jamie Delgado at the end of last season and he has been trialing coaches so far this year.
Jan De Witt was with him at the Australian Open with his former coach Daniel Vallverdu reprising his role at Rotterdam last week.
Neither were with Murray on a long-term arrangement, though, and he believes that is what he needs in order to raise his game.
"I'm just trying to get a more permanent solution so that I can have consistency in terms of the things that I'm working on, because having different messages from people who are working with you each week is not ideal," Murray said after losing to Felix Auger-Aliassime in Rotterdam.
"If I look at the beginning of this year and obviously the result [against Auger-Aliassime] didn't go my way, but there has been some positive signs.
"I really feel like my tennis can be a lot better.
"I don't feel like I lost because I was really struggling with my movement but I believe that my tennis can improve providing I put in the right work and consistently work on the right things for a period of time and I believe that will happen.
"It probably won't happen overnight because some of the mistakes that I've been making technically have been probably happening for 18 months or so, so it takes a bit of time to break those habits.
"I'll need to put in a lot of work on them to change that."