What does double entry accounting help you do that tracking gains & losses would not?
I use Gnucash (which is double entry bookkeeping software) to track all my assets, equity, expenses, income and liabilities. It's similar to Quicken in that I track every type of income and expenses. Gnucash uses "accounts" instead of "categories" which Quicken uses, but they essentially serve the same purpose for accurately tracking where every penny comes from, where it goes.
I also use Gnucash to track all my assets including valuable discretionary assets which I will depreciate (or appreciate) over time to the proper expense categories. This way I can actually see how much I am spending in a particular hobby for example, because the equity in an asset is not an expense, only until it depreciates.. the depreciated portion is the expense. These discretionary assets are "current assets", i.e. like cash, because I can easily sell them if needed in an emergency etc..
I even sub-categorize (sub-accounts in Gnucash) my grocery bill line by line so I can get a lot of categorical data to see how I can improve areas of my spending. It's nice knowing exactly where eveyr single penny is going.
At any time, in Gnucash, I can run a "Balance Sheet" report and it shows me my current assets , equity and liabilities. It gives me my total Net Worth (Total Equity) in that report. I want this report to reflect all my assets, both realized and unrealized. So this is why I created these "Unrealized Capital Gains" and "Unrealized Interest" investment sub-accounts in Gnucash.
Every penny is accounted for with respect to assets, equity, expenses, income , liabilties. Even unrealized gains. I love this Gnucash software. I realize for some, they dont both to track personal finances and only track their portfolios, that's fine if they are content with that. But I am on very limited income and I tend to let things get out of hand with spending not knowing how much i am really spending in each category. By tracking everything, every single penny in the proper sub-accounts (sub-categories), I know exactly how much -- and it has already helped me tremendously.
All of the data is manually entered into Gnucash -- no automatic bank account syncing -- and the data is stored locally on my hard drive. This allows for me to have extremely accurate (to the penny), up to date, records and structure the account hierachy (expense/income categories) as I see fit. I love the privacy, accuracy, categorical flexibility, and lack of account connection problems compared to what all the online services offer -- e.g. Mint, Personal Capital etc.
To me Gnucash is the best personal finance software ever and also happens to be free. (I used to use it for bookkeeping for my schedule c sole proprietorship when I resold used items on ebay, so that's how I got familiar with double entry accounting software.)
I've written customized spreadsheets to track my investments. For years, I deliberately did not track gains and losses - only percentage of portfolio. The goal was to encourage rebalancing, which it did - too often. I think the tools we use to view our investments can have a significant influence.
What influence does double entry bookeeping have on your approach to investing?
Mainly the bookkeeping software helps me with saving money by tracking income and expenses, and tracking all my valuable assets, including personal property at home. By saving more, I have more to invest.
p.s. Unsolicited investment comment: EDV has lost -13.4% this year because yields keep rising. I strongly suspect you will have more capital losses if you keep EDV.
Those tickers I have listed in the screen shot above, were just added the other day, as ones to research. Many of them I am not familiar with especially bonds. I just put them in there because these are ones people have suggested on bogleheads. My current IPS / plan is currently only in I-Bonds, VTI & BRK-B; I've never invested in any bonds other than I-Bonds. Of those listed above, I have only invested in BRK-B and VTI.
Here's my plan I made up the other day.. first plan I ever made:
https://drive.google.com/file/d/1d29YnOHH7bLAyurDQcbZ2k6aJOQ7Sjm5/view?usp=sharing