If you are going out on the mountains for a long day, then you should add extra drink and food. In the winter, the mountains can be very harsh.
If you suffer from feeling the cold easily, then put some hand warmers, and spare glove liners, which are cheap and can be worn inside a winter glove. Always remember that on starting a walk that you could encounter temperatures up to minus 10 degrees from whatever it is that day.
Walking poles are very important especially in the winter months.
Heading out for the day you should dress relatively light, using the layering system. Wearing heavy polos or fleeces does not work. Tights, light ones under waterproof pants work for most people and in the colder weather then you can buy good warm tights.
Include good boot socks and a fleece neck liner (not a scarf), very handy!
Always carry this gear when you leave home even if the sun is shining in Cork; it could be the complete opposite in Kerry or wherever you are going …
The good outdoor stores around town regularly offer “Starter packs” at a good price – so ask!