Hi Konstantino,
Answer 1: If you are using the Expert Advisor to trade with a Prop Firm then I would highly recommend setting up protections to keep from the possibility of losing your account. However, if you are using the Expert Advisors with a demo or live account with your forex broker then the decision of using protection is up to you.
Answer 2: After years of creating Expert Advisors Petko has learned there is no advantage of using trailing stops, in fact, it can actually cause the trader to lose more trades. Here is the reason: In the majority of trades the market will draw down by a percent or two before trading in the positive direction. With trailing stops this could cause your trade to stop out with a loss instead of going on and becoming profitable.
Alan,