LLC?

[D D]

A brief history before my question:

I recently obtained my realtor license and have been looking at investment properties for the past several months. Mainly, in the duplex/triplex market i Phoenix, AZ. Nothing has blown my doors off yet since my limit is only $90k but I am also considering starting a small computer repair/rebuild business. My question is this:

Should I form an LLC for each venture or group them into one? Of course it would be cheaper to form one but I am in the beginning stages of each but I like to form a firm foundation and make sure I am ready for each before I dive right in.