Working - Volunteer Very Carefully

Many people think if they say ‘Yes’ to everything, they will get noticed, get praised and get promoted. Not true. They will end up overworked, undervalued and abused.
Why is this person asking for volunteers?
How will this further my plan?
How will I look to senior management if I volunteer?
How will I look if I don’t volunteer?
Is this a dirty job that no one else wants?
Or is this person genuinely, desperately overburdened and really in need of my help?
Are you going to be seen as monkey?
Only step that one step forward when you are confident you will look good, gain benefit or make a difference to someone who needs help.