Hey guys,
I get your concern, but there is no 100% answer to that.
Usually, the brokers widen the spread when there is volatility on the market but that usually is the best time to enter into the trade and take quick profits.
Answering the very first question – it matters when you open the position. For example, if you want to buy, you will be buying at the Ask price and you will see a negative start for the trade – the spread. When the trade closes it will close on the BID price at that moment.
Or in other words, it matters at the opening and in the closing.
But you pay the spread one time. And actually, it is not actual “Pay the spread” there is no such a thing. It is just opening the long trade at the Ask price and closing it at the Bid price. The same thing applies conversely to the short trades.