I've read some articles saying it's a lot of hassle switching off mods, but they were written a few years ago, so I wonder are there any quick way of turning off mods now? I am going to switch between a couple of mods, at least.

No because Skyrim doesn't have control of your mods at all (well, outside the Launcher but you should never use the Launcher to manage mods)

Mods need to be activated or deactivated using a mod manager. There are three for Skyrim worth noting. Nexus Mod Manager, Mod Organizer and Wrye Bash. Each have their advantages and disadvantages.

Activating or deactivating a mod is as simple as checking and unchecking a box, but its more complicated than that. Mods install their own files, and just deactivating a mod doesn't remove those files, and the game may or may not still use them even with the mod deactivated, which can lead to unexpected results.

The more and more complex mods you use, the more difficult it is to shut them all off.

You can easily start a new game without any, but it's removing mods from a game in progress that's an issue. The save game remembers the state of persistent objects (such as whether you left a door open) and if the mod that provides the object is removed, then things may crash trying to load up a save, or on re-entering an area where something was removed.