The phrase "complicated to use" is correct and usable in written English.
You can use it to describe something that is difficult to understand or operate, for example: "This software is so complicated to use, even experienced users find it a challenge."
But I found the new phone to be complicated to use.
In addition, essential devices are often difficult to install, complicated to use, and expensive to maintain.
P.G.P., or Pretty Good Privacy, is one system to encrypt e-mail communications, but it is relatively complicated to use.
As for what to do about children of temporary marriages, the editor added, "It is not so complicated to use birth control anymore".
Some tools of this nature are already available, but they can be complicated to use or costly to implement; commercial services like Gmail and Facebook don't provide them.
"All those wacky wands on the market these days are complicated to use even for me as a professional," he said.
Besides, said Larry Barbetta, vice president of Siebel Analytics, a unit of Siebel Systems, "what were companies supposed to do?" "They couldn't just say the stuff we've been selling has just been way too complicated to use," he said.
It can be expensive (Predictable retails at £119.99), difficult to access or complicated to use (6.4 million adults in the UK have never used the internet) and it's no substitute for genuine face-to-face relationships.
He regards this as a technical necessity when dealing with dense, naturalistic dialogue: it's fussy and distracting to keep cutting between angles, and physically complicated to use camera track or dollies over long, uneven routes.
It is well described, but it is complicated to use easily.
This is because ultrasound diagnostic technology is complicated to use and costs thousands of dollars.
