hmm, let's see. if i was just walking around a house, i might take notice of

comfort:

what is the hvac system? if converted to forced-air, was the old ductwork reused? if so, and there is a/c, were air returns added, particularly on the second floor? how many?

what kind of windows? if they are original (this is a plus to many of us), are there modern storms for additional comfort? do they work?

is the attic insulated? can you access the attic? were the walls insulated?

do the exterior doors open and close easily? are there large gaps around them when closed? is there a storm door?

walls:
are the walls the original plaster or have they been knocked down and replaced with sheet rock? are the exterior walls plaster or sheetrock? if sheetrock, did they blow in insulation and nicely build out from the windows or is the work shoddy?

are the ceilings smooth, plaster, are they popcorn, are they some type of drop ceiling?

are there any wall cracks that wide enough that i can fit a penny into? (note that i am generally unconcerned about finer cracks)

from the basement:
what kind of foundation is it? poured cement? stone? cinder block?

find the main structural beams. either i-beams or multiple pieces of lumber together or in some cases just massive lumber beams. how do they look? termite damage? generally okay? find where the floor joists go into the basement or are supported on the side. how do they look? if a stone foundation, how do the joist pockets look (in older houses they would make a notch in the stone foundation to hold the joist...this is a common place of failure and if it is failed look for the repair and if it looks good).

if i'm suspicious about a joist, i would be poking it with a pen or something like a letter opener or a nail or whatever i have handy to see if they are soft.

still in the basement...where is the electrical panel? is it modern? is the wire coming in modern romex (plastic insulation), older two-wire in sheathing, or knob & tube? some combination of these? is there some indication the service panel was installed professionally (eg service tags)?

what does the furnace look like? how does the water heater look? is there plumbing in the basement? is the sewer stack (the giant pipe) old cast iron (often fine) or PVC (you know it was replaced)? are the water lines that i see copper (good), pex (good), or galvanized (less good)?

do i see evidence of water intrusion, either staining or the homeowners belongings stacked on pallets or otherwise lifted off the ground?

electric:

in addition to what i wrote above -- how many outlets per room? how is the spacing? are they grounded or ungrounded (3 prong)?

are there ceiling fans or simple lights? are there indications of partial rewires, for example, is wire run in external conduit? does the bathroom have GFCI outlets? kitchen? how many outlets are in the kitchen?

bathroom/kitchen:

when was the most recent renovation? are there multiple layers of floor? is it nasty or clean looking under the sink? how is the water pressure? how quick does the hot water come on? is there evidence of water damage on the ceiling below the kitchen/tub?

general:

how is the closet space? how high are the ceilings? are the doors original? is the woodwork and molding original? is there crown molding, is there a chair rail, are there built-ins or otherwise interesting woodwork? do i like the color? is the wood painted or unpainted?

do the interior doors open and close easily? what season is it?

is there evidence of water damage, particularly around chimney runs or venting systems?

are there any major floor sags? if so, have they been addressed is some way? what does the ceiling look like below the sag?

exterior:
what is it? brick? wood? vinyl? aluminum? something else? if brick, how is the mortar? has it ever been repointed? if wood, when was the last time it was painted? if vinyl/aluminum, when was it put on? if vinyl/aluminum, is it coming off? how are the seams? can you see the original material underneath anywhere?

how is the roof? what is the material? if asphalt shingles ("normal" roof), when was it last reroofed?

how are the chimneys? straight? how does the masonry look?

how is the porch? is it original? how is the wood? soft anywhere?

how are the soffits (this is the roof overhang, viewed from underneath)? do i see rotting wood? are they vinyl/aluminum or wooden? do i see animal entry points or evidence of critter homes?

how are the gutters? is there wood rot around the gutters, indicating that they clog? how far are the downspouts from the house? where does the rain go?

I'M TIRED NOW. Hopefully that is a good start. Take pictures of areas of concern and ask on here.

Thank you so much! That was incredibly helpful.

You are wise to ask. One needs to add up anticipated costs for improvements/upgrades, etc. before they make an offer and order the home inspection, etc. By that time one is quite committed.

In my observation most buyers are distracted by chatty agents and the numerous features that are added to sell a house. Even new paint can cloud the mind.

BTW, with any renovations (eg. bathroom) pause to look at the quality of the work. Agents are great at getting sellers to order "quick fix" solutions. Proceed cautiously.