What is really frightening is how unreliable modern pressurised systems are.
"Old" vented-to-atmosphere systems with a small vent and feed tank in the loft, go on for years and years; 20 - 30 years is not uncommon. However, the three modern pressurised systems I have inherited in various houses, have been nothing but a pain in the a**e, needing regular attention, blocked safety valves, re-charging expansion vessels and recharging water etc. Luckily I have the knowledge and skills to work out what has gone wrong and can fix it. But then you get boilers with built-in expansion vessels which require removal of the boiler to replace them - crazy.
In my cynical moments, I can't help wondering if manufacturers are deliberately creating far less reliable systems to gain money on repairs and resales.