Quickly switch from classic to lightning and vice versa - shortcut

Quickly switch from classic to lightning and vice versa:

Two ways:

First:

On bookmarks, keep the links to both homepage(s) - classic and lightning like for classic - https://eu1.salesforce.com/home/home.jsp -bookmark and for lightning - https://eu1.lightning.force.com/one/one.app#/home. Now, simply switch now.

Second:

Have those created as home page links and add to left menu.

Then for each frequently used object you want to work with create a lightning/classic link, with the ID as dynamic variable then you can view each object on alternate UI (select view in new window)

Example    

Lightning - /one/one.app#/sObject/{!Lead.Id}/view

Classic - /{!Lead.Id}