I spend 50+ hours a week in boots in a construction environment, so comfort, warmth and ventilation is all!
If you want a boot that can be used outside you need to specify an S3 class boot as they will resist the weather.
I'd dissuade anyone from wearing safety shoes or dealer boots in any environment where they can come in contact with metal, stone or wood at low level, e.g steel or wood stored at floor level. For that reason many construction sites ban them. Instead go for boots with a walking boot height sides which support and protect the ankles better and are warmer in winter
If there is any chance of standing on nail embedded timber or the like look for boots with mid sole protection. These boots are classes SBP, S1P and S3. Only S3 are weatherproof
If weight is a concern opt for composite protections as opposed to steel protection (toe caps and mid soles)
If you have sweaty feet choose a pair with GoreTex (or similar) breathable liners. You can also get GoreTex socks these days
Many of us are getting on a bit, and as you get older your feet tend to spread. Buy shoes that are too narrow and wear them occasionally and you get corns - buy boots which aren't wide enough and wear them a lot and you'll end up with bunions and possibly club toes, which can be painful or even cripple you eventually. Many cheaper boots are simply too narrow and some so called "wide fit" still use the same protective toecaps as the same size of boot in a standard width. In other words they might be wide fit on paper but they'll still wreck your feet because the toes are too narrow
If you do a lot of kneeling go for boots with moulded-on toe protection
So if you need a wide fit boot at a lowish price have a look for a Delta Sault S3 boot. Mid range there's a firm called Cofra who do quite a few wide fit S3 boots with GoreTex linings and composite toe caps/midsoles (I'm on my second pair of Cofra Tutenkhamoons), but absolutely the best boots I've ever had are the Germsn made Stietz Oslo II boots I had a few years back. The problem is that they are expensive, considering I tend to wear a pair out in 12 to 18 months, and they are very hard to find in the UK. By all means buy cheaper boots, but just be aware of the problems they can store up for you over the decades
One final point about boots - they are designed to be worn with work boot socks which are somewhat thicker than the ordinary socks worn with shoes, more skin to hiking socks These absorb sweat, help keep you warm in winter (wool) or cool in summer (cotton blend), but they also help to protect your feet from the boots, and in particular the protective toe caps
