Rock climbing is a very arm-heavy sport, as it mostly utilizes muscles responsible for pulling and holding. The muscles most used for these are your back muscles and your arms. Just like with lifting weights, these muscles can tear and get damaged, which causes the pain you may feel, but it's also what causes them to grow and get stronger.
Rock climbing requires you to pull much of your body weight, and to keep you on the wall and close to it. This means that your muscles, especially your arm muscles, with be very heavily used for this, and in ways that you may not be used to, especially if you are a beginner rock climber.
Your shoulders, all the way down to your forearms, are used to help you move from hold to hold, and to help you grip the holds and stabilize yourself on the wall. This means that you will be pulling much of your body weight on with your arms, and you will most likely be doing it in ways that will cause your muscles to go through the same process they would go through when lifting weights. They will get damaged, which is what will cause them to hurt, and it is also what will cause them to grow and get stronger. Eventually, as you progress with your climbing, they will hurt less.
Rock climbers shake their arms as a way of recovering during a route or in between routes. The purpose of this is to reduce the lactic acid build up in their forearms, which is referred to as being pumped.
There is quite a bit of controversy over the effectiveness of shaking your arms to help recover as there doesn't seem to be a definitive answer regarding if it actually works, and how. Many believe that it is better to shake your arms while they are above your heart or head, while many believe that it is better to do it when your arms are down beside you. Some also believe that shaking your arms doesn't have any effect at all, regardless of where or how you shake them.
Many climbers use a combination of the two methods, they shake their arms above their heads, and below, to their sides.
Some also believe that the effects of shaking your arms are mainly psychological, and that they don't have any physical effect or benefit.
There is no definitive number of times you can resole your climbing shoes. It just depends on the condition of your shoes, and on the fit you want vs the fit of the shoe right now.
Based on the different online climbing communities, the average number of times climbers get their shoes resoled is 4, though, some even do it 6 times.
In the end, it depends on the condition of your shoes. If the shoes are in relatively good condition, but just have holes in the toe area, then it's more than likely a good candidate for a resole, even if it is the 5th or 6th time. If the shoes are just very used up and beaten to the point where you have holes in other places besides the toe area, or the shoe is torn or just in bad condition, it may be time for a new pair of climbing shoes.
In addition to the physical condition of the shoe in terms of damage, it also depends on the fit you want to have. Climbing shoes made with leather tend to stretch quite a bit. The longer you have them and use them, the more likely they are to stretch. After a few years of use, many climbers feel that their shoes become "baggy" and not as tight as they were. If this is something that you actually want, then it's ok, but, if you prefer a tighter fit, and the shoe is already getting to be too loose, then it may be time for new shoes.
A resole does tend to make climbing shoes feel tighter sometimes, but this is not a consistent occurrence, and the tight feeling may only be in the toes, while the rest of the shoe still is quite loose. The tightness also usually only lasts for a short period of time.
The bottom of your climbing shoe is usually just rubber. You can take a damp cloth and just scrub what ever is on it off, usually everything comes off. If not, you can try more aggressive things such has household cleaning products, or brushes to break down what ever is on the shoe.
Rock climbing is relatively easy for beginners since the beginner routes are usually not complex, and actually resemble climbing a ladder. As the grades go up, so does the complexity and the difficulty of the routes.
Beginner rock climbers can usually climb a few grades up from the easiest one, even if it's their first time climbing. For example, one grading system for bouldering is v0, v1, v2... As you go up in the number, the climbing gets harder, new holds are introduced that are harder to grip and use, climbing moves become bigger and more difficult, and the route itself becomes more complex.
Many times, beginner rock climbers and even those who it's their first time climbing can climb between v0 and v3. Some can even go up to v4 and v5, though, this depends on the climbing gym, and the climber. If the climber is in good shape and has prior experience in sports that could contribute to climbing, they could very quickly go up to climbing harder routes.
As you go up the grades, the difficulty between each grade also goes up.
The two loops are meant to help you pull your shoe over your heel. Sometimes it can be quite difficult to pull the shoe over your heel, especially for those who choose to downsize their climbing shoes, and having just one loop may just make it difficult to pull it over your heel, and could also shorten the lifespan of the loop since it alone will have all of the pulling tension. Eventually, it can tear.
Adding another loop allows the tension to be more spread out, rather than all of the tension being in one point. It also allows more area of the shoe's heel to be pulled, which helps make pulling the shoe over your heel easier.
Taping up blisters can seriously help ease the pain and discomfort they cause. Though, keep in mind that if the tape is very sticky, it could rip the blister off when you take the tape off, so add a thin layer in between, just to not have the sticky parts on the actual blister. A band-aid is a good option for this, just put a band-aid over the blister, and then tape over the band-aid.
Many climbers also pop the blister, and then put a band-aid or tape over it. Though this may not be the healthiest option, but for some it is the most practical because it is quite uncomfortable climbing with blisters, even when they are taped up, and they may pop while climbing anyway.
As long as someone is supervising, climbing can be a safe sport, even for kids.
Most indoor climbing gyms also have climbing classes for kids, even for very young ages.
If you live near a climbing gym, it is worth giving them a call and asking. You can also ask about the structure of the classes and how the kids are supervised and looked after.
