I do a zero-based budget on the fictional basis that I bring home $2550/month, even though my monthly income has never been this low since I got my current job. My reasoning is that I was able to live on less than this, pretty comfortably, in the months right after I graduated from college, and I don't want to fall prey to early lifestyle creep (I'm 23).
My health insurance and weekly contribution toward my FSA are taken out beforehand, so I don't include them. Additionally, my parents currently pay for my cell phone plan because they get a discount with 4 lines, but I have saved extra cash to pay them back annually for my portion of the plan lump-sum.
Budget of $2550:
Savings, Fixed: $675
$425 to retirement (not including employer matching which starts in a few months, exciting)
$200 to my Money Market account (just completed an $18,000 emergency fund; savings past this will go toward a down-payment eventually)
$50 to my mutual funds (low because I don't yet feel I know what I'm doing and want to learn more before truly investing)
Spendings, Fixed: $1,025
$1,000: Rent (I know how high this is, both in general and as a portion of my budget and income, but it's actually a fantastic deal for an amazing apartment in an extreme HCOL city. I have 1 roommate who pays $1100 for the larger room)
$25: Wifi (my half)
Spendings, Variable: $850
$60: Heat/hot water/electricity (my half. We've been well in excess of this during very hot or cold months, so to make up the difference I generally don't buy new clothes if the utility bill is high)
$80: public transportation (I work from home and can walk most places anyway, so I don't buy the more expensive monthly unlimited pass and instead fill up my card $20 at a time, with 4x/month refills as a maximum I've ever needed)
$40: ubers/other transportation (basically this will only cover 1-2 uber trips, so it's a rarely-used "safety fund" if I need to get home late after a night out and don't feel safe to walk or take public transportation. I sort of resent this category because it's really the price I have to budget for Avoiding Harassment from Men)
$200: groceries
$300: eating/drinking out (all non-grocery food, cafes/restaurants/bars, drinks, takeout, delivery, etc. I don't really limit myself here, because 1. I need to get out of the house to avoid cabin fever when working from home, and this often means buying something to sit somewhere nice where there's wifi and other humans and 2. I'm only going to be young and single in a fun city for a short window of time, so this is the most I'll ever be spending on going out, which I'm comfortable with. Luckily I am small and rarely manage to consume more than 2 pricey cocktails per weekend anyway!)
$40: toiletries/laundromat/cleaning supplies/makeup/sanitary products
$50: clothes
$80: miscellaneous (might include buying gifts for others, entertainment such as movies or museums, books, jewelry, etc. In the winter, I pay $45/month for ClassPass out of this category, but there are enough free exercise options the rest of the year that I don't need to have a gym membership.)
Rollover:
I rarely spend the full $850 of the variable categories. At the end of the month, I roll any extra money into a Rollover Fund, which, as the title implies, rolls over from month to month. It slowly accumulates in my checking account and in my budgetary spreadsheet, but I otherwise do not touch it on a regular basis. If I ever go over budget, I pull from Rollover so that I don't need to touch any of my savings or my emergency fund. The Rollover Fund is then used for annual or rare purchases like paying my parents annually for my cell phone plan as I mentioned, my annual renter's insurance (about $100), haircuts, replacing/repairing furniture or an appliance as needed (but would not be considered an "emergency"), or, in theory, a vacation, if I really accumulate a lot in this fund. Right now, my Rollover Fund has about $1,200.
But Wait, There's More:
This is simply the money I pretend to be making, when, in actuality, I am making a bit more. So, it's not really zero-based after all. For four-week months, I net about $2,625. For five-week months, I net about $3,235. This varies slightly depending on overtime, as well. It also doesn't include holiday gifts/bonuses, or income tax returns. On five-paycheck months, I put an additional $106 toward retirement automatically. The rest has built up my emergency fund (though a good deal of it is childhood and during-college savings). Now that it's funded at $18k, which feels like all I could possibly need given that I have supportive family who I could live with/turn to in the event of some personal apocalyptic crisis, I am not certain how I will allocate the Secret Money that Doesn't Exist in my mind.
Long-Term Extra $$$:
I suspect that I will keep this extra liquid enough to steer it toward a down payment. I think it'll be a good idea for me to invest in real estate in my city, especially a fixer-upper condo, as I have the time and know-how to do a lot of the work myself. A down payment in my city will be slow going even if I get reasonable annual raises, but I have time on my side, and I think I'm being quite careful about lifestyle creep. (And, uh, if there's some guy's income in the equation at some point, that'll speed things up considerably.)
This also does not take into account my pension(!) which I just don't fully understand yet and might only be relevant if I stay with my employer for quite a while. It also doesn't feel right to calculate anything based on it when I would assume that the employer will make changes to what it entails at some point/s in the next 42 years. Though I do plan to stay with this job long-term, I need to understand more about it before I really think about it as a long-term retirement budget thing.
TLDR:
I'd really appreciate input/advice on this! I'm just starting out and my goals are not super set or calculated past "stop renting when possible." I know I'm only a bit past 15% on retirement account savings, but I've been basing this off the notion that if I work my short-term budget with the very long-term goal of toward owning 2 properties and renting 1 out, after having bought them relatively cheap for my area and fixed them up at low cost, the passive income on this will be worth more than putting a couple extra dollars in my retirement account right now, and, then, FIRE will have a clearer outline. None of this truly takes into account the fact that I want to get married and have biological kids, which is sort of my whole goal in looking into FIRE, but it feels odd to plan around an unknown number of small people who likely will not exist for another 10+ years. :)
Thanks!!