when you tear into a piece of equipment and there are lots of different hydraulic lines that are taken off, what do you do to remember what goes where??
Colored zipties or paint marker, if you're really fancy you could also have painted caps or plugs.
X2 on the colored zip ties. Paint marker works if you have one that works on oily surfaces. I also make a quick sketch- red goes here etc. - that sort of thing. I also note what both ends connect to just in case a tag gets lost. Hint - if you have a complete parts book for the machine that is a great source for figuring out where things go. It really saved me when a previous owner tried to change the control pattern on an excavator.
Snap some pictures with cell phone. If you can get old underground phone line with lots of colored wires they work good too
I use 50 pair phone cable. I have a 2 foot long chunk. I also take pictures. Helps to remember what line gose on this/that side.
a marker, to put unique marks on the fittings. then a picture with the cell phone. quick and permanent... nothing to fall off or get lost.
A center punch. The first connection, punch a dot on the hose nut and the fitting. Second connection, punch two dots on hose nut and fitting. Repeat for 3, 4, 5, 6, etc. Won't wash off in cleaning/handling. Permanent mark. More than 6 marks, plan B.
I have a bunch of 5/16" flat washers stamped with numbers in pairs, 1-20. Zip ties or tie wire to attach them. Learned that trick on excavator swivels. Paint markers don't hold up to brake cleaner.
I have stamped caps and plugs with numbers to identify where things go. Sometimes its hard to have enough caps and plugs though.