If you clear the cookies in your browser you will lose the content of your Watchlist.
If you create a Watchlist on your desktop computer, it will not be available to your smartphone or laptop, as cookies are specific to the machine and browser that they are created on.
Why can't I see my watchlist?
If you have already created a Watchlist, but it is not being displayed, it may be due to one of the following reasons:
You have cookies turned off.
You have cleared the cookies in your browser, which results in the loss of the content of your Watchlist.