Well maybe it is as simple as letting the user enter a % growth rate. Future stuff is a guess anyways unless you get something with a fixed rate of return or you have some history to back it up. it would be on the user to make that initial guess and you could help them track the history. With investment accounts you could have revaluation entries users would add whenever they got a revaluation on the account(weekly,monthly,yearly,whenever) to set the true value on a specific date. you could then back set the % rate from the last time the account was valued and show it to the user either on the entry bar or just on a chart somewhere. you could also let them set a estimated rate going forward which is what would be used to calculate the daily valuation for each day going forward. The default % carried forward could be the last time period’s actual %. Or you could use radio buttons and let the user select whether they wanted to use the last period’s % or continue to use the estimated % from the previous revaluation entry. this way if there was an investment that was expected to live in the 7% ballpark and it had an unusual spike or downturn but was expected to level back out , the user could select the previous rate instead of the spike rate. And of course you would want to have a user entry option in case they chose none of the above.
Using the above method would play right in to paying off debts both fixed and variable. For a car(or other oddly depreciating items) account you would use two entry types(maybe 3). One for the loan and its rate. One for the actual car value and the depreciation rate the user sets. you could maybe suggest a rate on a simple curve (or maybe just a straight line) and just let the user revaluate whenever they wanted. If the user is really hyper-serious about networth down to the dollar then they need to revaluate everything they have anyways and then run the networth chart. Simple depreciation rates would allow them to get a ballpark figure at a glance and make coding much easier. The third entry type could be for a loan against the account like a lien or a home equity loan. you could do that third entry type against any asset(home,car,401K)
I think investments and assets are viable account types. Users wouldn’t have to use them (the simple path), but could start adding them as they got more interested in truly mapping out their value. i wouldn’t push them too far to the back…
Sorry this got long, hope it makes sense.