In my first apartment I purchased a shop vac - The tiniest, least expensive one they make. I was poor and didn't have very much space. It worked well enough, but I often found myself wishing I would have gone just one size larger, to handle larger areas more effectively.
Nearly a decade later I bought the next size up, and experienced the same emotion. A little over a decade ago, I found myself buying a new shop vac, the next size up. Same thing. When I bought it, I really waffled over the size I purchased versus going at least one size larger (which would have put me in the larger nozzle size and the attachment that is long enough to use while standing upright).
Not a month later a neighbor had a pipe burst in their basement. That larger shop vac would have been SO much better for helping with clean-up.
Around that same time, I purchased an air compressor- the smallest one I could find (again, to save money). It was for keeping car and bike tires properly filled. It served (and still serves) that purpose well. But since then I have found myself wishing I would have gone bigger, in order to run a nail gun, staple gun, and paint sprayer, as well as one with sufficient power to use to blow out dirty vacuum filters, air conditioner compressors, etc...
Fortunately a neighbor had an extra one of sufficient size and I was the lucky beneficiary. It has been so nice!
I also bought a cheap reciprocating saw somewhere back then, and I cheap mitre saw. The mitre saw has been very sturdy, and I am very happy with it, however it is small, and I have found myself wishing on many occasions that I had one capable of cutting boards larger than 2x6.
The reciprocating saw, I really didn't expect to use much - I really purchased it for one project. I have since discovered a number of other projects, but having only used it maybe a dozen times, it is already threatening to break. It is extremely difficult to seat and remove blades.
There are two lessons learned:
1. Pay a little extra for better quality on tools, even if you don't think you are going to use it all that much. You will likely save yourself money in the long run.
2. Strongly consider buying tools that are more/bigger than you currently need. You again may save yourself money in the long run, and you may find future projects for yourself, or freinds/neighbors which will benefit.
PS. Note - I am not saying go into debt, I am saying wait a little longer and save up for better (refer to my first "regrets" post).