Q:

How should I manage my charging cycles to extend battery life?

I use my laptop throughout the day for various work. My usage starts sometime after breakfast and continuous into night, till about 9 pm, then breaks for dinner and continues for another hour or two. During this entire while, my laptop obviously gets discharge a couple of times. What I currently do is, I plug it in whenever the battery drops below 25% and keep it plugged till it goes back to full. This repeats in cycles. I usually encounter about 3 such cycles.
Of late, I have grown more conscious about this, and each time I plug it for charging I get worried that I am actually damaging my device instead of preserving it, given that I am constantly sitting next to the AC power supply but yet making my battery work hard throughout the day.
Is there any way I can optimize my usage, to achieve the end goal of extending the general durability and endurance of my battery device?
TL;DR: I frequently charge my laptop and I sit near the AC supply all day. Any way to optimize my battery life in this specific situation?

A:

Batteries have a finite life, there are a lot of different aspect involved in a battery life; however the one we concern about here is "Cycle life".

The cycle life is the number of complete charge/discharge cycles that the battery is able to support before that its capacity falls under 80% of it's original capacity. [1]

In an other words:

In general, number of cycles for a rechargeable battery indicates how many times it can undergo the process of complete charging and discharging until failure or it starting to lose capacity [2]

What you are doing is repeating this cycle over and over and thus decreasing your battery's life.
Remember that you shouldn't let your battery to be charged to 100% of its capacity over and over and also reach to the 0%. 
So the best thing to do is controlling the charging process. 
Based on your laptop there might be different tools available to you. For example if you have a "Lenovo ThinkPad" you can use tlp to  easily manage this process.
It got a bunch of configuration items which makes us able to control battery's charge thresholds:
START_CHARGE_THRESH_BAT0=75
STOP_CHARGE_THRESH_BAT0=80 

Charging starts upon connecting AC power, but only if the remaining capacity is below the value of START_CHARGE_TRESH (start threshold). Charging stops when reaching the STOP_CHARGE_TRESH (stop threshold) value. If, however when you connect the AC adapter, charge is above the start threshold, then it will not charge. [3]

So we can keep our AC plugged-in all the time while we are controlling the charge process. Something between 60% to 65% while you always using AC is a safe number to go with.  

