Is roof renovation for an old roof sensible?

Hello everyone, I would like to hear your opinion on the following problem:

I am asking here for an acquaintance:

They are currently renovating their house, the façade company has just applied the insulation. The same company was also supposed to do a roof renovation (cleaning + sealing). The roof is easily 50 - 60 years old, the tiles are already chipped in some places, moss and lichens are on it. The battens are okay as far as we can see. There is no underlay, so rain can certainly be pressed in by the wind and then lands on the fiberboard or in the insulation between the rafters. However, it dries again there, no mold problems currently – no vapor barrier or similar either. The roof is mostly used as an attic. Everything is somewhat open except at the dormers and on the slopes in the upper floor. There was only a problem in one place on a dormer roof, where we changed the beams because they were rotted. There a chimney of a gas boiler was apparently not installed correctly – it was replaced, it looks clean again.

Roof pitch 48 degrees, somewhat less about 20-25 degrees at the dormers. Roof covering: red tiles.

Now the company tells us that they recommend re-roofing the roof because the tiles are already so weathered. Costs 10-15000 euros. But the money is not available right now, no chance.

Now the two are arguing about this: One party wants to have the roof sealed (about 4000 euros), this comes with a 10-year warranty. During the 10 years then save money for a new roof. The other party claims the warranty is only for the color and does not bring a big increase in roof durability itself. This party would put the money aside to have enough saved in 5 years to do the roof anew if it ever becomes leaky.

What do you think?

I’ll keep it short, variant 2.

If there are any damages or water can penetrate somewhere, sealing the tiles won't help you either.

Does the roof hold, with minor repairs if necessary, for another 5 years? If yes, the sealing is a waste of money.

Yes, I see no problems with that. A few roof tiles are still there.

A few loose thoughts:

[*]What is meant by roof durability anyway?

[*]If there is no money now, then maybe there won't be any in 5 or 10 years either.
[*]Warranty issues can be clarified objectively and contractually agreed upon.
[*]New tiles are only good for the appearance. Do not do it, as there is no money.
[*]I would only do sealing now if despite the repairs moisture is an acute problem and the sealing can definitely solve the problem.

The tiles are already chipped off in some places, moss and lichens are on them. The sub-battens are okay as far as we can see.

I would just go up in the summer with a safety harness and a coarse broom to remove moss and lichens and, if necessary, replace cracked or broken tiles. Such a new coating won't do you any good in terms of tightness. It's only for appearance. If the roof is tight now, why should anything change in 5 years? Once a year, preferably in summer, go up, clean it, replace anything broken, and keep living.

We also had our now 60-year-old roof inspected by two roofers. Of course, both wanted to reroof it. One eventually admitted that technically it's not necessary. The connection points should be tight (chimney, dormers), the tiles not moss-covered, and everything firm. If something is loose, renew it and preferably check annually. The only real problem is if it's leaking and you don't notice it and something stays damp permanently, like once with your house.