For many general admission standing concerts, people tend to get to the venue hours before the event stats to ensure a good spot. I am usually one of the crazy people that will wait anywhere from 2 to 10 hours for particular acts. If you are thinking about lining up (or queueing) early, there are many different factors to determine how early you should/would want to get to the venue. Here are some important things to think about when preparing for your general admission concert.
1. Weather/Time of Year
The time of year definitely impacts how early I get to a venue because if its the middle of the summer, I might be sweating the whole time and possibly get dehydrated out in the sun for hours upon hours, likewise if its winter I might be freezing and get frostbite. **Granted this might not apply to everyone, but the places I live have very hot summers and very cold winters.** But when choosing what time to get there, make sure you put the weather into consideration. Even if its a nice spring day, if it rains you want to be, at least somewhat prepared.
2. Size of Venue
The size of the venue definitely makes a difference of how many people will be lining up. If its a smaller venue, chances are less people will be waiting outside all day and if its a bigger venue, more people will be.
The size of the standing area/general admission also plays a part. For instance if you're going to a large venue, but only a small pit area is the general admission standing area and everywhere else has seats, then people probably won't be spending all day waiting to get a spot in a small area, but it largely depends on the artist you're going to see.
3. Type of act/ Fanbase
Sometimes the size of the general admission area doesn't have much of an impact if you are seeing a well-known artist. If you are going to a big venue and seeing a big name artist, people are going to be lining up pretty early, whether there is a small pit or the whole floor is general admission.
For example, on Justin Bieber's Purpose Tour, he had two types of setups on the arena tour. Both had two pits on each side of the stage with about 50 people. One setup was the rest of the arena had seats, but the other setup was that the whole floor was standing. Whether or not the floor was standing or not, people who had pit tickets on either side of the stage often got to the venue early in the morning or even camped out. Because Justin Bieber is so big, it didn't matter that only 100 people were in the pits, they were still going to camp out all day. However the shows that had the entire floor standing, some people camped out for days to be near the front. The same happened at shows for Twenty One Pilots (only recently after they blew up).
If you're not familiar with the fanbase, try looking at past concerts on Twitter or Instagram to see if many people usually line up early for their shows to try and gauge how early you want to arrive at the venue.
4. Pack Lightly
You definitely want to pack as lightly as you can. If you plan on lining up for a while, it is best if you're able to drive to the venue and park nearby, especially if its in the winter months. If its very cold outside, you want to be bundled up and try to stay as warm as possible. Bring coats, blankets, and anything else you might have. Sometimes people are able to set up tents as long as you take them down at a certain time set by security (usually when more people start arriving, for bigger concerts I would guess they would have to be put away by or before 11am.)
If you do have a car, you can also take turns or have someone hold your place while you go in the car and warm up a bit. Then later on you can put all of your things back in the car, no later than an hour or two before doors open.
If you don't have a car, you can still do this, but there's a good chance you won't be able to keep the things you brought. If I have to take public transportation, I know not to get to the concert too early if its freezing out. I buy cheap blankets and the aluminum emergency blankets to keep warm with. Coats can be difficult to decide on if you don't have a car. Look online and see if the venue you're going to has a coat check and how much they charge. Keep in mind, if you do plan to use the coat check, there are a bunch of people in line behind you that probably won't use the coat check, so if you waste time checking a coat, there's a good chance a lot of people will get in front of you. If possible I try to just tie my coat around my waist once I'm inside, but I have lost a coat that fell off once so make sure you are able to keep track of it.
Bag sizes usually depend on the venue rules. Some venues only allow small bags with clear guidelines of how small they must be while others will allow backpacks. Again, look online before you go and make sure you are bringing something that will be allowed in. As for food and other things, I bring a grocery store bag with food, water, etc. that can be thrown away before going into the venue so I don't have to worry about fitting anything in my bag. (plus food and drinks are not normally allowed inside.)
The best advice I have for parking is check on the venue's website. They usually have the best information if the venue is in an area you are not familiar with.
6. Venue Rules
Venues have different rules for different things. Check on the venue's website a week or more before the show and research anything you might have questions about. Check for their bag policies and if they have any rules against lining up early or camera usage. Camera's aren't usually a problem anymore but some venues can be weird about it and might not let you bring in a digital camera.
If you still have questions after looking at their website, reach out to the venue either by calling, email, or on social media. I recommend doing this at least a week before the show because they usually take a while to get back to you and have a higher number of calls/emails if you wait until the day of or the day before the concert. If they don't answer you in a day or two, try again or if you emailed them, try calling. This way you will get your answer in time for the concert.