What advantages does power steering have? My understanding is that it’s only beneficial in low speed situations like parking…
Is it necessary? Is it more necessary for certain applications like off-roading? Racing etc?
Also wondering since my power steering leaks anyway, if I could just switch it with a manual one?
Almost certainly not unless your vehicle had an option for unpowered steering like a Honda from the early 90s. Just order replacements for the leaking parts from Rockauto or through @TLAR’s wholesale connection.
Manual steering is almost always geared differently to account for the lack of hydraulic or electric assist. Do not use a power-steering equipped vehicle without functioning power steering except as a last resort, and then, only to get somewhere that you can get patched up.
Just echoing everyone here you would be better served fixing the power steering.
I do have both types of cars with and without power steering so can tell you about each.
The heavier a car is the more effort it is to turn so you don’t normally see heavy vehicles without power steering.
Off-Roading you absolutely want power steering when your wheels get stuck in a track you will be unable to muscle the car to where you need it. I would also expect that if you hit a major bump that caused your tires to rapidly change direction you could break your wrist. (can’t say I have ever tried this)
Racing - Within my circles people would say you don’t want power steering as you want to feel the road. Personally I think there are pros and cons but ultimately personal preference (NASCAR uses Power Steering)
It is difficult to make low speed maneuvers without power steering vs having power steering in situations like parallel parking.
Ultimately in your situation I would fix the system, generally there are not many parts to fix.
Power steering is very beneficial in endurance racing since it reduces the steering effort required of the driver. The truth of this is demonstrated when your power steering fails in the middle of the race and your arms, shoulders, and back are shot after a stint in a way they never were before.
You can convert a power steering rack to be unpowered. You see this in some limited racing situations (we are doing it for a lightweight mid-engine project), but I wouldn’t recommend it for a street driven car. Here’s a pretty good how-to, if you should ever be interested in that:
https://motoiq.com/project-miatabusa-part-5-de-powering-the-steering-rack/
Our endurance race car is power steering and I wouldn’t get rid of it – in fact, we’ve spent a lot of time and effort troubleshooting it to eliminate the leaks. P/S systems are very high pressure in certain places, so that’s one reason they tend to spring leaks. I wouldn’t get rid of P/S except in very limited circumstances.
With dead power steering three disadvantages come to mind:
I’ve driven a vehicle where the power steering failed for quite some time. It was neither a fun experience nor something I’d recommend. It was also more than a tad unsafe.
Only, if the model came with a steering box that had no assist, even then, I would be hesitant unless there was no other option or parts available. P/S has become a necessary creature comfort. 
Also, with no mention of vehicle type, we cannot know if other stuff is powered from the “power steering” hydraulics. Powering brake boosters, and cooling fans is not uncommon, and some systems power other things, still…
I think it’s an 87 Ranger.
Aw hell.
I see that, now.
Hm.
I’d probably convert that bad boy. They’re nice and light, so effort is no biggy. The boxes appear to be readily available…
https://www.buyautoparts.com/autoparts/Ford/Ranger/Manual_Steering_Gear_Box.html
Probably cheaper to replace hoses.
a power assisted steering system is completely different than and manual/non power assisted steering system
There are too many idiots on the internet and ebay selling “kits” to bypass a traditional belt driven power steering system to eliminate the hydraulic feed to the rack (Rack and Pinion systems) and this is not a “good plan of action” .
Nathan,
I’d suggest you stick to what you have a repair what leaks. There is no sense in re-engineering or retrofitting something that may not work for your truck.
I don’t know about these kits. I did see a manual gear at the salvage yard a couple weeks ago that would be compatible tho and it made me think. I pretty much agree about fixing what I got, just wanted some ideas or opinions. The steering noise is getting worse and I drive everyday, my truck is not a “toy”. But just in case I ever get off the road I can see the advantage of a hydraulic steering assist.
Thanks everyone!