!important to use or just don't be bothered.

If I am making changes to BP-Social based on my examples below (just examples not real) do I still need to use !important However, I might want to add my own custom divs and classes later.

It seems like there are some pros and cons here but I will appreciate some clarity on this.

I already started making lots of changes to my BP-Social Theme without the !important

your css

#blog-entry {
float: left;
width: 685px;
border-right: 1px solid #ddd;
margin: 0px;
padding: 0px 10px 0px 0px;
}

my changes

#blog-entry {
float: left;
width: 685px;
border-right: 1px solid #999; (changed color)
margin: 0px;
padding: 0px 10px 10px 0px; (changed one px)
}

or

#blog-entry {
float: left;
width: 685px;
border-right: 1px solid #ddd;
margin: 0px;
padding: 0px 10px 0px 0px;
background: #c0c0c0 url(../images/myimage.jpg); (my new line)
}