You should never feel pressured to buy something, especially an expensive solar energy system. These types of salespeople are pretty common in this industry. You can tell them you'll be back later, and they should be fine with it. If they are persistent about making a deal now, tell them that the deal should be just as good in the future. Making decisions under pressure can be more costly later on.
Once you buy a system, one of the first things you will notice is how quiet your solar cells are. As they draw in energy from the sun, they make absolutely no noise. This is something that most owners appreciate, as all other renewable energy sources make some noise as they operate. Particularly if you have a stressful job or a stressful life, the last thing you need is a noisy system interrupting your few moments of peace.
If you know that you cannot reach your solar panels to clean them, the best thing to do would be to hire a professional to clean it for you. if you are not sure of who to call, you should ask the company that came and installed the panels for you.