In my (limited) experience, I think of an inspection as an insurance policy. It's there to catch potentially expensive surprises that aren't obvious from a walkthrough at a regular showing.
You should factor in any repairs / updates that are obvious from your showings in your offer. For example, you would expect to pay less for a fixer-upper than a recently remodeled house.
You should already be committed enough to a house when buying an inspection that you will proceed with buying it if there are no major unexpected surprises.
If there are surprises, it's reasonable to try to negotiate them, but it's not a guarantee that the seller will negotiate. If the seller does not give you the accommodations you're seeking, you will have lost time, but you will have actually saved yourself money: had you gone ahead with the purchase, you would be faced with unexpected expensive repairs.
EDIT
As pointed out in the comments, there are important differences between insurance and an inspection:
- An inspection is not guaranteed to find every problem. It will NOT find any problems in inaccessible areas,
- There’s no guarantee that what is found is correct, and
- There’s no recourse for either of these.
So, don’t expect an inspection to make you whole if there are problems later, but it can do a lot to avoid common but expensive problems that lay people would miss.