This is one of those questions that the answer is -" It depends". But let me offer an overview. The older the home, the more potential for upgrade cost. If the house does not have updated grounded electrical that is a cost for some point in the future. Copper plumbing is another one associated with and older home. Many were made with stainless steel pipes that by now are showing their age. Other items like the furnace or air conditioning age may be a factor when looking at updating expenses. Last but not least, the roof age and the condition of the foundation.
If you are looking at a home in the mountains or beach area, there may be cost associated to retaining your property line. If erosion is a factor, there may serious cost to be considered in maintaining retaining walls and the foundation.
If you have a septic tank and not public sewer, be aware that tree roots can damage the drainage system. Equally, if you have a well, changes in the under ground water table may require re-drilling for water.
You mentioned taxes but if you are in a more rural area and sidewalks have not been installed, this may be a cost in assessments later down the road. ( no pun intended) Also, look for easement issues on the property. This should be disclosed but it is always important to read the title and deed carefully.
If you are purchasing the home as an investment and will be renting, many times new investors underestimate maintenance and repairs. Sometimes rental property situations require legal action, so adding the cost of legal representation may be something to consider.
If you are obtaining a conventional mortgage loan, look for hidden cost from the lender. Question every fee and I recommend having a back up lender to help you question any charges on the paper. If the first lender doesn't come through, you already have the back up lender who knows your situation and is ready to go. Talk to lenders before shopping to compare "typical" cost for completing the loan.
Make sure you obtain all the appropriate inspections before your contingency period is over. Check into the "general plan" for the city to find plans for new highways, or other activities that may alter your home value.
Here's some food for thought ....
When you purchase a home there's a few little monthly bills that most current buyers have kinda forgot about.
You have property taxes and depending on the what and where, it can and does increase you monthly payment by $200/$400 a month.
You now have things like homeowners and maybe flood insurance, that can easily run your payment another $150/$200 a month depending on the area.
Minor things like water bills, depending on the area (and if you have kids) it might cost $50/$75 more a month.
Buyers forget about the simplest things like the electric/gas bill .. again, depending on the area and the time of year you might easily be seeing $250 a month just on budget billing.
Of course we all have to have cable, we can't miss the Sopranos, right.? .. before you blink you can be reading a $150 cable bill a month.
Phone is always the "sleeper", thats because folks are using cell phones and they forget that extra $100 a month.
Hey before you know it, there's at least another $900 floating along with that monthly mortgage payment....
Most times, it's best to be low in debt and high on life....
* That leaky roof that needs to be replaced
* The lateral sewer to the street needs to be dug up and replaced
* appliances that die (washing machine, refrigerator)
* major maintenance to your HVAC system (rusted heat exchangers, or new compressor)
* lawn maintenance
* water bill rises dramatically, or heating bill due to rising fuel costs
* a leaky window (or one left open during a storm) causes damage to drywall, or plaster from the 2nd floor, all the way down to the dining room.
* mold remediation from the leaky window... yuck...
* the exterior paint begins to peel... fresh paint job
* the fence is falling down, needs to be replaced
* re-blacktop the driveway
you get the idea... it's ongoing and never ending. Welcome to the wonderful world of home-ownership!