Money spent on tools and fixtures isn't really wasted, it depends upon how much you use it. If you will use something only once or twice, you may want to farm out that portion of the work. If you enjoy restoring and fabricating, the sky is the limit. (if you are talking for a paying shop rather than a hobby, depreciation works into the equation too) I usually have 2 or 3 projects going at one time, and finish about 1 or 2 a year, tops. I buy alot, but still farm out engine machine work and body off and on work. I can't justify the lifting equipment and rotisserie for as little as it would get used.
my rule of thumb, if it fits in the toolbox, on the shelf or in a cabinet, I'll buy it.