Q.I keep checking the box to stay signed into my Gmail account when I log into the Firefox browser on my Mac, but when I quit the program, the browser never retains the information and I have to keep logging in and typing in the security code that gets texted to my phone. How can I get Firefox to remember me?

A. If you are booted out of your Gmail account each time you quit and reopen the browser, make sure you have cookies enabled in your Firefox settings. While browser cookies — little strings of text — can be used by advertisers to quietly identify you when you visit certain sites, they can also store login information for websites like Gmail.

To get to your cookie controls, click the three-lined Menu icon on the right side of the Firefox window and select Preferences. (These settings are under the Options icon in the Windows version of Firefox.) On the Preferences screen, click the Privacy icon on the left side to see your cookie settings;if you do not see separate settings for cookies and browsing history, use the drop-down menu next to History and select “Use custom settings for history.” If Firefox is configured to delete all your cookies after you close the browser, your login preferences are being dumped as well.

Once you have set your cookie preferences, try logging into your Gmail account after ticking the box to stay signed in. If Firefox still does not keep you signed into Gmail, try clearing the browser’s cache. (To make your surfing faster, the cache stores images and other bits of websites you have visited, but these files are temporary.) To get to the cache controls, go back to the Firefox Preferences screen, click Advanced on the left side and then click the Network tab in the window.

If you still cannot stay signed into Gmail, go back to the Firefox Privacy settings, click the Show Cookies button and delete the cookies the browser may have stored for Gmail and other Google sites. Log in again after turning on the checkbox to stay signed in — and see if Firefox remembers this time.

Note that if you manually sign out of your Gmail account when you quit Firefox, the “Stay signed in” setting is turned off.

Prolonging Laptop Battery Life

Q.I am about to order a new battery for my Dell laptop. In the wake of starting anew, what exactly is the best way to prolong the life of a battery? Some sites say it is best to keep your battery charged between 50 and 80 percent, but others say it is best to let your battery drop all the way down to zero and then charge back up to 100 percent. I want to be able to work on my laptop for as long as possible without having to plug in. How can I best achieve this?

A. The Laptop Battery FAQ on Dell’s support site says the old habit of fully draining the battery before recharging it is a technique used to keep older nickel-metal hydride (NiMH) batteries operating as best as they could. Doing so with the more common and modern lithium-ion batteries does not improve their performance, and a complete discharge may damage the battery itself. If you do not plan to use the laptop for four days or more, charge the battery before you go away, but do not leave it plugged into a power source. Dell’s site recommends charging the battery for about an hour (to get it around 80 percent charged) before shutting down the laptop and storing it.

With typical use, a rechargeable battery does wear out and you will probably notice the time you get between charges start to lessen after about 18 to 24 months. When ordering a new battery, check to see if a high-capacity version is available for your laptop model. Although large-capacity batteries may weigh more than standard-capacity power cells, you get more time away from the electrical outlet.

Once you get your new power pack, you can find further tips for prolonging its life on Dell’s site, which has a page of battery performance tips. While you are running the laptop off its battery, you can help prolong its charge by using a Windows power plan to conserve as much juice as possible by dimming the screen and turning off other unnecessary functions.