Our first house hunting experience was quite intresting. We looked at tons of homes over a 9 month period. I have done plumming, electrical, home maintenance the whole 9 yards. We would look at a house, and I would write down everything that needed to be repaied. I then came up with an estimate, and we would keep looking. Some I figured to need about $10,000 in work (done by myself........not paying others to do it). Then we found a house, sold by owner. The wife fell in love with it, and I found minimal problems wrong with it. I figured about $800 in repairs.
Well............we recarpeted the house $2,400, we had ot put a new roof on it (with repairs to the sub roof) $3,600, we added on a deck $1,200, a shed $1,400, and a new dishwasher (because the old owners lied to us about what they were leaving us) $400, changed all the locks and replaced a door $180, the furnace went.....so replaced that and added central air $3,200, new gutters, $200, painted the house after ripping out some rotted wood and replacing that $500, replaced the faucet's, BR sink and the BR floor another $400, and the hot water heater on our own to switched from electric to gas $300.
Anyways, the bottom line is, whatever you think the house will need, it will need much more.
We then built last year, and it was an awesome experience......our builder was awesome, everything went great. It's a 2200 SF ranch, with a 3 car garage and an 800 SF finished basement/playroom, with another 1500 SF of storage area on the other side of the basement.