Such as? What's your favorite?
I use whatever algorithm gets me out of the water the fastest, VPM+2, Buhl 20/85, or ratio deco.
For short dives, ratio deco makes the most sense, I know that full deco bottles will outlast the duration where ratio deco is useful. For longer dives, I cut tables using VPM or Buhl, develop a trend, and (roughly) stick to it. I don't really care about 5min of deco one way or the other on these dives, because % wise, it's very little.
For instance, my last deco dive was at Ginnie Springs, just shy of 170min using back gas which was 28% Nitrox, 2 stages of 32% nitrox, and 1 stage of 21/40 trimix (for buoyancy reasons). For my starting point, I assume everything is 30%. I know that 3 AL80 stages and 2xLP108's cave filled have around 500cu ft of gas, of which we're going to use 1/3 in and about 1/6 out with the flow observing 1/3rds, so let's assume usable gas is (1/3+1/6)*500 = 250. From figuring a rough estimate based off of SAC calculations, previous experience in this cave, and guess work, we assume that this will get us 150-180min of bottom time-- the high flow caves really murder your SAC, and it's super low for the beginning of this dive on a scooter, so it's a huge gas range and we know this.
Now let's see what decoplanner has to say... This is an estimate, but even the algorithms are, so I'm OK rounding.
Now, let's find a trend between bottom time depth and deco time. Yellow is our target range. We'll notice that at 90ft avg depth, every 5min beyond 160min of bottom time results in 2min extra 02. So 20min over, add 20/5 = 4 *2min = 2min deco. 10ft shallower = 50% less deco. 10ft deeper = 50% more deco.
OK, these are crude estimates, but the potential for unknown is in this area, so knowing how long we can stay, what depth and what that does to our deco gas is extremely important. We can't pull tables out every 5min of the dive, so a general trend is a huge convenience when making on the fly decisions involved in cave diving.
Now, assuming a full AL40, and SAC of .5 (kinda high for deco), I know that an AL40 will give 50min of deco time at 20ft. I also realize that 32% nitrox takes (roughly) 2x as long to deco out as o2 in the case of a failure, so if my buddy and I split that bottle, we're each going to get 25min on o2, and 50min on back gas, so knowing "on the fly" how many minutes of deco we have allows ourselves to know what we're committing to.
Because of this deco gas limitation, I also know in the back of my head the entire dive that the following ranges (in red) are off limits.
Once back to deco, I refer to my tables, but I always try to develop an easy to remember formula for the potential range of depth and time for each dive I do. It's very quick to look at, and can make on the fly decisions much easier and more educated.
Admittedly, if you handed me a navy dive table without directions, I wouldn't know what to do with it. Of course, if you gave me a PC running OS/2 I couldn't use it either, and they're equally as useful in my mind, so I'm not too worried.