In another response I mentioned looking for PCB router/milling machines, these seem like idea solutions to your sheet metal processing.
There are many issues that effect cutter life, Spindle RPMs, feed rates and depth of cit have to be tuned for optimal tool life, which also has to be balanced against quality. Actually running one tool for 24 hours is pretty impressive. It isn't uncommon to have to change cutter or inserts several times in one shift. One thing that might help you here big time is an automatic tool changer which would allow machining with the biggest tool possible for the task at hand.
Use cutters suitable for the task at hand. This is where a router with tool change capability can do wonders for you. You can have the machine select the right tool based on size and material. For example when doing aluminum with these small cutter is is often common to use a single flute cutter.i have other jobs and i cant tie up the machine for 24 hours...if you were to be milling complex small shapes from brass, copper or aluminum what blade would you use??..
You are actually becoming a CNC machinist by getting involved this deep. The knowledge doesn't come overnight
My first thought here is that your feed rates are slow for the spindle RPM. Also what are you using for lube/coolant. The next ugly thing to realize is that metal machining can be a bit dirty. Actually greasy or slimy, which is another reason to prefer a totally enclosed machine. Lube varies with the material being machined but aluminum often does surprisingly well with WD40, in othe materials WD40 is just about useless. On top of all of that cutters now come with coatings that are optimized for the materials being machined.
im currently using a 1/16th carbide flat end mill and i also tried one of the needle point v shaped engraving bits..a single job ruins that blade too and also take 24 hours to cut a single job of 30 of these pieces
Once you settle on a machine you will need to revisit proper cutter selection.