I would like to illustrate some of the common issues I find when inspecting balconies so that you have an idea what you may be concerned with.
I love balconies here in town because we have so many high rise condos with absolutly wonderful views.
OK lets get started.
Balusters should have no more than a 4 inch gap the same as with a stairway and there should not be any type of pattern such as out of cast iron that would allow for chidrdren to climb up and fall over the guardrail.
Try not to leave anything climable near the guard rails either.They should be at least 36 inches tall by the way.
I do not recommend my clients try this but the guardrail should also support 200 lbs of pull.
Many balconies have glass panels and these should be made of tempered safety glass.
Look in lower corners for a sticker also known as a bug.
Check guardrail fastners and connections for any that might be missing or not secured properly and remember any openings in exterior wall covering can cause water intrusion issues.
The above includes possible openings left by light fixtures or electrical outlets which of course need to be GFCI protected so you are not harmed and shoud at the least have spring loaded covers on a weather proof box.
Many balconies are either cantilevered making them appear to float in air or have turnbuckles attached to the wall at each side above and may also have diaginal bracing from below.
If the decking is say concrete or any solid surface it is important that it be angled at least 1/4 inch per foot to the outside for rain runoff unless there is an internel drain.
While outside you may also wish to check the exterior wall and see if you observe any issues.
Be sure to check the entrance door also for any obvious issues such as a bad door frame ,window seals gaskets,trip hazards,etc.
What really gets me is when some developers put in a balcony door with no door closer or door stop that prevent the handle from shatering a $1,000 peice of glass.I have found this at to many new downtown high rises in Chicago during my inspection process.
I will add some more later if I think of anything that might help a buyer on initial walkthrough.