Matching duty cycle to actual workload, rather than just chasing the highest amperage figure, is the difference between a machine that keeps up with the job and one that keeps tripping out halfway through it, and it's a question worth raising with a supplier before you buy, such as plasma cutting equipment.
Buying a first welder is easy to overthink. Rather than starting from a shortlist of machines, it helps to start from the work: what materials, what thickness, and how much of it will be done indoors versus outside or on-site. That single question narrows the choice between MIG, TIG and MMA far more usefully than comparing spec sheets in isolation, whether you end up looking at a Jasic entry-level MIG package or something further up the range.
Flap discs sit between cutting and grinding in terms of use, combining overlapping abrasive flaps to blend welds, remove coatings and finish surfaces with more control than a solid grinding disc. Every disc also carries a maximum operating speed printed on it by the manufacturer, and checking this against your angle grinder's rated speed is a basic habit worth building into every new batch you open.
Getting the right disc for the material and finish you're after saves both abrasives and time, and it's worth checking your current selection against the job list with a supplier who stocks a full abrasives range, such as TIG welding equipment.
Duty cycle is one of the most misunderstood figures on a welder's spec sheet, yet it tells you more about real-world usability than the headline amperage does. It's expressed as a percentage over a ten-minute period at a given output, so a machine rated at 30% duty cycle at its maximum amperage can run for three minutes out of every ten at that setting before it needs to rest and cool.
Ambient temperature and airflow around the machine also affect real-world performance. A welder working in a hot, poorly ventilated space, or https://www.yell.com/ one that's been boxed in against a wall with no clearance for its cooling fan, will hit thermal cut-out sooner than the same machine used with proper clearance in a cooler environment. Keeping vents clear and giving the unit room to breathe protects both the duty cycle you paid for and the components inside.