If you're climbing a Munro in Scotland it's recommended to go in a small group as it's safety in numbers. However if you do decide you prefer going it alone make sure you tell people / mountain rescue  the route  you are heading on, and the time you expect to be down from your carefully planned route. Don't rely on a mobile phone as it can be useful tool but will have limited / no reception especially in some of the remote glens.
Never underestimate the Scottish Weather as it is renowned to be changeable in all parts with the West Coast being the most unpredictable due to the weather systems coming from the Atlantic Ocean. Even in the summer months there can be freezing temperatures, howling winds and freezing rain on the summits, ridges and belaches even if the morning started as a calm sunny day. Always keep an eye on the forecast and keep an eye out for the weather posters often pinned up around the highlands giving mountain weather forecasts for the next few days.
Always take a few layers of clothing with you to protect you from the cold along with water proofs, hats and glove are also recommended to be taken up even in the summer months.