Volunteering can be a touchy subject for me, as I have had bad experiences with volunteers, such as those that wanted to come in "weekend warrior" style and solve a problem in as short a time-frame as possible. In doing so they carried out their self-assigned duties in a shoddy manner that had to be repaired a short time later, or worse, damaged property beyond repair.
For example, the last time my family moved there was some mishandling of property that caused damage. We could never have managed the move without the help, but with a little care there would have been no damage at all.
Obviously I think volunteering is important and it can be a significant blessing to those who need it, but volunteers need to be certain they are prepared to do the work that is needed, and not the work they want to do. If not, a volunteer should seriously consider donating their resources in another way.
Volunteers need to know that they may not always understand why a task needs to be done in a specific way or within a certain time-frame; people in need often have requirements that they understand but have difficulty conveying to others without a significant investment in time and effort. It is good to understand why people have their individual needs, but sometimes it is only necessary to understand that there is a legitimate need, no matter how odd it may seem on its surface.
For example, due to my extreme sensitivity to dust, pollen, mold, most cleaning products, and so many other things I need regular cleaning at a frequency that seems obsessive, and often to an extent that can appear to be very eccentric, and sometimes those who are helping me don't believe me. It takes a long time to explain the years of effort, trial and error, and help that led to the discoveries of what exactly works and what doesn't.
I caution any potential volunteer against the idea that, because someone in need rejects a specific offer of help, that they don't actually need or want some kind of help. If ideas are being "shot down" one after another, the proper response is to ask, "What do you need, and how can I provide it?" Then listen. Sometimes the answer will be "I don't know" and sometimes the answer will be complex.
Before eBooks existed I had a lot of trouble handling books due to my severe sensitivities to papers, dyes, and inks. I wanted access to a textbook and a friend was offering to make the book available to me laminated, or in plastic sleeves, which unfortunately was an idea I had already tried it and it didn't help. After a back-and-forth of several minutes my friend figuratively threw up his hands and said, "Well, if you don't want my help..." Admittedly I could have handled that situation better, because I appreciated his willingness to brainstorm ideas. Thankfully it wasn't long before the first eReaders became available and I was gifted an Amazon Kindle.
And at the risk of sounding cynical, please never volunteer unless you intend to carry through. Saying you will do something for someone then never showing up leaves that person wondering. Wondering when the help will eventually materialize, whether they should look for help elsewhere, or wondering if they are going to get help at all.