I have a problem opening too many tabs while web browsing in Google Chrome or Firefox; how can I fix this?

Try to minimize the number of tabs open. How? If you opened a tab that you find interesting but don't have time to read now, use http://getpocket.com/ (Read it later) extension to read it later when you have time. Mark it and close the tab. You can read it whenever you are free on your PC or mobile device even when you are offline. https://support.mozilla.org/en-US/kb/tab-groups-organize-tabs on Firefox. The help you focus on the task at hand by moving everything else in the background. Clean up Tab Groups every week sorting them into read later, action now and close. Don't use bookmarks. I've tried using  browser bookmarks and other online services like delicious to store  bookmarks but I never go back to them. Tab groups are more convenient to go back  to. Organizing tabs in tab groups:

On chrome, you can try this extension Tab Wrangle, which can automatically close inactive tabs after a specific time period (say, five minutes?). One firefox, there is a relatively different addon called "Close other tabs", which may be worth trying.

I tend to open the tabs take a cursory glance, see if it is interesting or long and I'd use some kind of read later service. And close the tab.  I prefer http://getspool.com to queue my side reading. YMMV

There are many good ways mentioned. I’d also like to recommend one more - XBrowser. it’s a feature ‘Read-later’ with no need for plug-in. Hope it can help you. There is: https://play.google.com/store/apps/details?id=com.mmbox.xbrowser.gp

Bookmark webpages whenever possible. Then close the tab. If you're overloaded, just file it away & ctrl+w. If you have spare time you'll return to it. Every now and then, clean out your bookmarks to remove the ones you don't have time to explore. Delegate to other services whenever possible. If it's an article, save it to Pocket. If it's an actionable item, add it to a to-do list of your choice. If you want to save it for reference, clip it to Evernote. Etc. In general, get tabs out of the way as soon as possible, and file them to a place where you'll be able to access them again. Cloudmagic is then a great way to search through all the stuff you've saved.

I'm the developer behind Flanity. It lets you effectively switch between tabs by shortcuts and search. It has a very simple and intuitive interface. Please try it out here: https://chrome.google.com/webstore/detail/flanity/lggbgmacejmglpoipjablediabgmdiln/related?utm_source=chrome-ntp-icon

have really cleaned up their bookmarks section. I suggest do really look into that. They have followed their own philosophy and is incredibly intuitive and simplistic.

People keep many browser tabs open as a way to keep track of stuff they want to read or watch later. It's kind of like a to-do list. Unfortunately this slows down and makes unstable (i.e., crash-prone) both your browser and computer. I use iCrumz to save the tabs I want to keep track of to look at later, which allows me to close the tabs and reopen them later when I'm ready to look at them. iCrumz is a free, cloud-based website bookmarking tool. It works with any Web browser, operating system or device (computer, tablet, smartphone). It lets you organize all your bookmarks on a single page in columns of collapsible folders using a drag/drop interface that makes them easy to organize and find. Doesn't require Flash, ActiveX, Java, Silverlight, Unity or any other installation, extension or plugin. And no ads! Because it's a cloud-based solution, there's no need to import/export/sync your bookmarks between browsers and devices. Just login from any Internet-connected device and your bookmarks are all there just like you left them. And you can add keywords and description metadata to each bookmark (in fact they are automatically pre-populated when you create each bookmark). [disclosure: I am the CEO of iCrumz] https://iCrumz.com