Can't have too many tools in my opinion, unless they have a power cord. What I can do in two minutes with any of my rasps I can screw up in 2 seconds with a power tool.
I have a Nicholson rasp that is flat on one side and half round on the other, but it is not one of the better 49's or 50's, no numbers on it, just Nicholson. Also have an old Nicholson four way, got two more of the new ones made in Brazil and neither one will cut cotton candy. Lotta guys love those sureforms, but I have bought two different types and have taken a hammer to both of 'em in frustration. Felt mighty good at the time, ya know.
Get a bunch of those old cheap foam rubber mouse pads that every company in the world used to give away, put them all over your bench and set your rasps on them, one rasp per mouse pad. Make a habit of that and you will have them last a lot longer. Every time a rasp hits another metal tool you lose the cutting edge of a tooth or two, it starts to add up.