What size and colour?
Black, black buckle, 24mm
Or even black with a thin blue stripe.
Will I need one of these little toolkits too?
What size and colour?
Manufacturers will typically tell you every 5 years and with them directly. In practice it can usually be longer than 5 years and if you don't wear a watch everyday the oils will stay in good shape longer. Some people wait for signs of reduced accuracy before a service others stick to the book.
That watch has an eta 2824 movement which is one of the most used mechanical movements and any watchmaker will know it intimately and be able to get parts for it, to service it. So while Longines may suggest you service with them, there is no real need (when out of warranty).
Black, black buckle, 24mm
Or even black with a thin blue stripe.
Will I need one of these little toolkits too?
Mrk,
Where you get the strap from ?
Their site just says an authorised repair centre so I guess it won't need to be sent to them directly. What about seals and pressure testing, can most non authorised places be relied upon to do that properly? Do they also restore the finish to the bracelet and casing as opposed to just movement servicing? If so then it could all save a bit if money!
nato/zulu will work for any watch with bars
you need a spring bar tool to remove your current strap, put the pins back in, then thread the nato on
Timefactors do nice natos at not silly prices.
edit: having looked up the DZ1198, looks like the strap has a screw so you could probably unscrew it (or cut it off) and avoid buying a spring bar tool
same movements, similar style, pays your money makes your choice
tag bomb in terms of used value, don't know about Longines, don't see them much on enthusiast sites