Answer

 These do come with a 3 year manufacturer’s warranty.
 However, the warranty only covers manufacturing faults and doesn’t cover damage to the glass during use. Also, the heating element is only covered for 12 months.
 These (and most other) water stills must be hard-wired into a 15A mains spur, and for this reason do not come with a 3-pin plug fitted.

 Water stills do require regular cleaning / maintenance, although this depends on the quality (hardness) of the water input and how much the still is used. The manufacturer recommends cleaning these every few weeks if used regularly or the water is hard, but it should not need doing as regularly if used less often or the water is softer. However, if they are not cleaned, and scale is allowed to build up, then the heating element can fail or become damaged.