This depends on your DIY skills and how complex the install, and there are plenty of DIY kitchen ideas. Fitting cabinetry is within the scope of someone with decent joinery capabilities. However, gas or electrical appliances have to be installed legally by a registered professional with the relevant certification.
'Someone would need competent skills in carpentry, tiling, plumbing and building work,' says Asad from Glam Kitchens. 'They'll also need the right equipment. For example tools to cut and install worktops, cut tiles, and carpentry machinery. It’s important to note that a good kitchen fitter can make a cheap kitchen look beautiful and expensive. But an expensive kitchen in the wrong hands can have the opposite effect.'
'Some appliance manufacturers and retailers offer an installation service that includes the removal of old appliances,' adds Damian from BIKBBI. 'Otherwise, these will need to be done by a qualified gas engineer (Gas Safe registered) or electrician (NICEIC/other regulatory bodies).'
'Our recommendation would be to appoint a professional installer. They'll have a good understanding practical installations, legislation requirements and, importantly, trouble-shooting experience and expertise.  Installation is complex as it covers multiple trades, regulations and competencies.'