Is it hard to change a track bike back into a normal street bike (motorcycle)?

I have been looking for a first motorcycle and notice alot of people trying to sell their "track bike". just curious is it hard or impossible to change a track bike back into a normal street motorcycle? and would it still be considered street legal afterwards? what should i look out for as since it was a previous track bike that would make it not worth buying? (ie bent forks ... wear and tear or what not?

To turn a track bike into a street legel bike, you need to do a few things. You would need a head light, tail and brake light and I would also recommend front and rear turn signals. You would also need the bikes title so that you can get license plates. Depending on your state it may need to be inspected by a Department of Transportation inspector (DOT).

All depends on what is missing which is probably the headlights and and that would depend on if they were totally removed or just covered or taped over. If the bike has a custom racing plastics in front with no headlight holes, then that has to be replaced.
Turn signals, and other lights will have to be replaced IF missing.

Other than that and having to put a licence plate on it, I can't think of anything else that would prevent it front being street legal.
As far as possible damage or wear being it's a track bike, you could take it into a motorcycle shop for a checkover, but they may charge you a fee. If it's private sale, you have a better chance to test ride it to determine if everything is okay and that the engine runs well, controls work and frame is good. There should be an even amount of compression from the bikes front forks and rear shock absorbers which may just have to be readjusted IF the rider made changes to them for racing purposes.

track bikes take an enormous beating. The clutch, pistons, rings, sprockets, chains, and other key mechanics are usually worthless on a track bike for sale.

They keep them well maintained and swap out often when in use. Once they give up on the bike as race worthy, you're stuck with whatever mess is in there.

A lot of good points by the other answers thus far, only thing I would add is that a lot of track bikes have a 'salvage' title, or no title at all. Depending on which state you're in, that may be an easy fix, or a really difficult one.

no its not so hard but a track bike normally are only sold when maintenance cost or a complete rebuild of bike has to be done
if you are not mechanically up to date skip it, it will neat a lot of work to keep going for a reasonable time on the road

call your local bike shop or dealership that does the inspections ... they'll tell you what you need on a bike that'll make it street legal and what's needed to pass inspection