Older Swedish Stamps Still Valid For Postage?

Has Sweden ever demonetized its postage? How far back are older stamps still valid for postage in Sweden?

I know that most pre-Euro stamps from European countries are no longer valid for postage, but since Sweden never adopted the Euro, I'm not sure which of their stamps are still valid.

I just purchased a collection that has a ton of semi-modern postage, booklet panes and the like.

Interesting question and one that I'd be interested in as well. I don't have the answer but I collect Sweden on a rather casual basis. Not only have they not adopted the Euro, I don't think they've ever revalued their currency, either. They've also been remarkably politically stable (particularly by European standards), not having any revolutions or foreign occupations during their stamp-issuing history.

I emailed Jay Smith and he informed me that to his knowledge, all Swedish postage back to 1858 is still valid for use today.

Another good reason to collect Sweden. My main collecting focus is elsewhere at the moment, but I do aim to collect Sweden on a more serious basis at some point in the not-too-distant future. It's one of the very few countries that I collect to the present day, due in large part to the fact that there's no logical cutoff date for stopping. I stopped collecting many other countries at the introduction of the Euro or when there was a major political change. There are no such clear points in Sweden's stamp-issuing history. Plus, the design and production qualities of their stamps are generally excellent, and they don't go totally overboard with the number of new issues.

I just received the collection today, 4 volumes of fun. While my emphasis is on the used material for the cancels, some of Sweden's engraved material is just gorgeous in post office fresh condition.

I have a complete MNH Sweden collection from 1945-1990 and most used before this period.
I have all the booklet panes too but I wouldn't consider using them for postage as they are catalogued far higher.
SG lists some of these panes from the 50's and 60's at £30 or more.

Don't be misled by artificially high catalog values. SG is obscenely high on most things (true of all countries, not just Sweden). I have yet to find any area where SG prices even approach reality, at lease not here in the U.S. or online.

Most ebay listings I see that are priced via SG tend to go unsold unless they are ultra-high grade. For run of the mill material, SG is way off base, IMO.

Of course SG is a retail catalog ala Mystic, since they are selling based on their catalog, so I expect the prices to be artificially high... which is why I virtually never use SG; I don't like the inherent conflict of interest. Only if there is a variety I cannot find in Scott, Facit, or Michel, will I look it up in SG for comparative pricing and then convert to "real" pricing.

I never use SG merely for pricing but it is indicative of relative scarcity so I stand by the point that certain items I would not use for postage.
IIRC the panes in question have a similar price in both Michel and Facit.
Still overly inflated as they never sell for anywhere near that.

Don't think I'd describe SG as having an inherent conflict of interest. They do what one would expect someone producing a catalogue to do - offer to supply the goods within it. They've been doing this for 160 years. I'd consider the non-retail books "price guides", rather than catalogues in the classic sense. Not, actually, that I use SG's catalogues for price information - their value to me is in the information about stamps.