Invented in 1830, the original lawnmower would be recognizable to day. The same basic parts were in place at the beginning. Though not gas or electrically powered, the twisted set of blades did an admirable job of keeping grass low. The reel mower was a welcomed replacement for hand scythes, though of course it took a while to catch on.
Now, lawnmowers are everywhere. More often rotary today, they still cut the grass to within an inch or four in height and are usually gas powered. But beyond that, choosing a good one takes some research.
Acquire a few brochures or check out the websites of the brand you're considering. Find out what their failure or replacement rates are and how often they have to be maintained. Manufacturers differ. Some have engines that almost never need tuning and oil replacement may be needed rarely.
Lawn care professionals often use a type of reel mower that shoots cuttings out the front, leaving a fine mulch. The result can be a golf green smooth lawn. But they're more expensive. However, if you have a very dense, short blade grass such as Bermuda or St. Augustine they're worth investigating.
The more common type is the power rotary, invented in 1939. The push-type will typically be about $100 less than the self-propelled variety. For most lawns they will do a fine job and the extra money for a self-propelled type may not be justified.
Self-propelled lawnmowers will save a lot of pushing effort, but they still have to be turned so the benefits are limited. The amount of turning can be so frequent that having the mower propel itself saves only moderate effort, in some cases. Whether the extra cost and potential maintenance issues are worthwhile is a matter of personal taste and reliability or reputation.
Consider the type of lawn you have and whether you want to pick up grass or leave it down for mulch. Even today many are designed as if the engineer never used one. Whether the bag should be in back or the side depends to some degree on preference. But much depends on the size and shape of your lawn. A wide open area can accommodate a side bag easily, but that's less common today.
Rear bags will typically hold more clippings, but that can mean pushing a heavier mower as it fills up. Side-bag units are often lighter and less expensive. When considering which to buy, try to test out removing the bag and replacing it to see how easy or difficult the task is. Apart from the effort, this also gives you a clue to whether the manufacturer has used solid quality parts.
Once the plastic components of a bag are broken, replacement is usually your only option. Bag replacements are not cheap and sometimes impossible to find a year after the initial purchase. Here again, the final choice is a matter of preference.
Check out the blade and other metal parts. Steel costs less, but rusts more readily. Aluminum doesn't rust so readily, though it does oxidize this is less of a problem here. Some modern decks on which the motor sits are heavy duty plastic polymers and very sturdy.
Select carefully and your lawnmower could last 10 years or more. Given the high cost of a mower, it's worth the effort to do some homework before purchasing.