Hello i'm a lvl 62 holy/disc priest spec for plus heals and dmg for spirit. I can heal any instance up to now with no problems and most of time really easy. i have 757 plus heals and 458 plus dmg and 7.4k mana so i also have had no problems soloing sense hitting out lands. i've lvl this way from the beginning while when i first started out i had a lot of trouble soloing after getting higher it got easier with better armor. but i still mostly instance lvl because i find it more entertianing and more fun that way and slightly faster i personally think so i only quest when i can't find a group which isnt that often being a strong healer and instancing as much as i have i know a lot of people that are always inviting me to group. plus as a holy or holy disc priest u will be able to find a good guild easier because guilds are always looking for healers.